RU2795511C2 - Method of manufacturing paper or cardboard - Google Patents

Abstract

FIELD: manufacturing paper or cardboard.

SUBSTANCE: invention relates to a method for the manufacture of paper or cardboard, including the addition of polymer P to an aqueous suspension of pulp, dehydration of the specified aqueous suspension of pulp containing polymer P on a water-permeable substrate to obtain a wet paper structure with a solids content of 18.5 to 25% by weight, and additional dehydration of the wet paper structure to obtain paper or board. Polymer P is obtained by polymerization (i) between 33 and 83 mol. % of monomer of formula I

in which R¹=H or C₁-C₆-alkyl, (ii) between 6 and 56 mol. % of diallyl dimethylammonium chloride, diallyldiethylammonium chloride, or a salt of a monoethylenically unsaturated monomer containing a quaternized nitrogen atom, which is the only charge-containing group at a pH value of 7, (iii) between 11 and 61 mol. % of monoethylenically unsaturated carboxylic acid, monoethylenically unsaturated sulfonic acid or monoethylenically unsaturated phosphonic acid, or their salts, (iv) between 0 and 50 mol. % of one or more ethylenically unsaturated monomers other than the monomer (i), (ii) and (iii), where the total amount of all monomers (i), (ii), (iii) and (iv) is 100 mol. %, and subsequent hydrolysis of the N-C(=O)R¹ of groups contained in the units of the monomers of formula (I), polymerized to obtain polymer V, with formation of primary amino groups or amide groups in the polymer P, where at least 87% of the units of the monomers of the formula are hydrolysed (I).

EFFECT: resulting paper or paperboard has good dry strength.

10 cl, 6 tbl

Description

The present invention relates to a process for making paper or paperboard, comprising adding polymer P to an aqueous pulp suspension, dewatering said aqueous pulp suspension containing polymer P on a water-permeable substrate to obtain a wet paper structure having a solids content of 18.5 to 25 wt. %, and additional dehydration of the wet paper structure to obtain paper or board. The resulting paper or paperboard has good dry strength. Other objects of the present invention are paper or paperboard obtained by this process and polymer P.

The following trends in today's paper industry sometimes have a significant adverse effect on the dry strength of paper or paperboard. The amount of recycled paper waste continues to grow. This is accompanied by the use of shorter cellulosic fibers and the use of inexpensive raw materials is usually attractive. It is a constant challenge to reduce the density of paper or board in order to save raw materials. Water circulation in paper machines is constantly decreasing. Therefore, of interest are processes for the manufacture of paper or paperboard which provide good dry strength of the resulting paper or paperboard.

DE 19815946 A1 describes polymers obtained by a free radical-initiated polymerization reaction of N-vinylamides and optionally monoethylenically unsaturated carboxylic acids containing from 3 to 8 carbon atoms, for example acrylic acid or maleic anhydride, and optionally other copolymerizable comonomers, for example styrene, and subsequent hydrolysis of the polymerized amide groups with caustic soda. These polymers are used in a process for retanning chrome leather to produce upper leather.

In DE 35 06 832 A1, the manufacture of a paper sheet is described in the examples by dewatering an aqueous pulp slurry containing no additive, by dewatering an aqueous pulp slurry with a preliminary addition of cationic polymers, and by dewatering an aqueous pulp slurry to which a cationic polymer and an anionic polymer containing carboxy groups are added. . Cationic polymers are polyethyleneimine, poly(dimethyldiallylammonium chloride), a condensation product of adipic acid and diethylenetriamine crosslinked with epichlorohydrin, poly(N-vinylimidazole), and polyvinylamine. The object of the invention is to increase the dry strength by adding a combination of a cationic polymer and an anionic polymer containing carboxy groups.

In WO 2004/061235 A1, the object of the invention is to increase the strength values of manufactured paper sheets in which partially hydrolysed poly(N-vinylformamide) and a second polymer are added to an aqueous pulp suspension before dewatering. The second polymer is a cationic glyoxylated polyacrylamide or anionic carboxymethyl cellulose.

In DE 102004056551 A1, the object of the invention is to increase the dry strength of the produced paper sheets, where at least partially hydrolysed poly(N-vinylformamide) and an anionic copolymer containing an anionic acid are added to the pulp slurry before dewatering. The anionic copolymer is obtained by copolymerization of 30% acrylic acid and 70% N-vinylformamide.

In US 2008/0196851 A1, the object of the invention is to increase the dry strength of manufactured paper sheets, where both a vinylamine-containing copolymer obtained by the Hoffmann decomposition reaction of an acrylamide copolymer and an anionic polymer are added to the pulp slurry before dewatering.

Additional processes are needed to make paper or paperboard where the paper or paperboard has good dry strength.

According to the invention, a process has been developed for the manufacture of paper or paperboard, comprising the following steps:

(A) adding a water-soluble polymer P to a first aqueous pulp suspension having a solids content of 0.1 to 6 wt. %, thus obtaining a second aqueous pulp suspension containing polymer P,

where polymer P is obtained by

- proceeding with obtaining polymer V radical polymerization

(i) from 33 to 83 mol. % monomer of formula I

in which R ¹ =H or C ₁ -C ₆ -alkyl,

(ii) from 6 to 56 mol. % diallyldimethylammonium chloride, diallyldiethylammonium chloride, or a salt of a monoethylenically unsaturated monomer containing a quaternized nitrogen atom, which is the only charged group at a pH value of 7,

(iii) from 11 to 61 mol. % monoethylenically unsaturated carboxylic acid, monoethylenically unsaturated sulfonic acid or monoethylenically unsaturated phosphonic acid, or their salts,

(iv) 0 to 50 mol. % of one or more ethylenically unsaturated monomers other than the monomer (i), (ii) and (iii),

where the total amount of all monomers (i), (ii), (iii) and (iv) is 100 mol. %,

And

- hydrolysis of the NC(=O)R ¹ groups contained in the units of the monomers of formula (I), polymerized to obtain polymer V, with the formation of primary amino groups or amide groups in the polymer P, where at least 87% of the units of the monomers of formula (I) are hydrolyzed , polymerized to obtain polymer V, in terms of the amount of all units of the monomers of formula I, polymerized to obtain polymer V,

(B) dewatering a second aqueous pulp slurry containing polymer P on a permeable support to form a wet paper structure having a solids content of 18.5 to 25 wt. %,

(C) dewatering the wet paper structure to produce paper or paperboard.

In the present invention, "dry matter content" is defined as the ratio of the weight of the sample after drying to the weight of the sample before drying, expressed as a mass percentage. Preferably, the solids content is determined by drying at 105° C. to constant weight. This is done by drying at 105° C. (±2° C.) in an oven until constant weight is achieved. A constant mass is achieved if, at a solids content of 1 to 100%, the percentage value rounded to the first decimal place no longer changes, and when the solids content is from 0 to less than 1%, the rounded to the second decimal place no longer changes. decimal place expressed as a percentage value. Drying is carried out at ambient pressure, possibly at 101.32 kPa, without correcting for any deviation due to weather conditions or altitude. In the section devoted to examples, in the paragraph under the heading "Determination of solids content" describes a practical implementation.

In step (A), the first aqueous pulp suspension means a composition comprising (a-a) water and (a-b) pulp containing cellulose fibers. An alternative term for "pulp suspension" is "pulp".

Mechanical and/or chemical techniques may be used to form the first aqueous pulp suspension. Thus, for example, milling an aqueous pulp suspension is a mechanical technique for producing shorter fibers and, in the case of cellulose fibers, also for defibrillating the fibers. The degree of dehydration of the aqueous suspension of the pulp is also determined by the provided degree of grinding. One method for determining the degree of freeness of a pulp suspension is to determine the kinetics of dewatering according to the Schopper-Rigler technique and it is expressed in degrees Schopper-Rigler (°SHR).

All wood fibers or annual plant fibers commonly used in the paper industry can be used. Annual plants suitable for pulping are, for example, rice, wheat, sugar cane and kenaf. Examples of mechanical pulp made from, for example, softwood or hardwood include mechanical pulp, thermomechanical pulp (TMP), chemothermomechanical pulp (CTMP), pressurized pulp, semi-chemical pulp, high yield pulp, and refined mechanical wood pulp (PMM). Pulverized wood pulp typically has a freeness of 40-60°ShP, in contrast to standard groundwood pulp having a freeness of 60-75°ShP and fine fine wood pulp having a freeness of 70-80°ShP . Pulps derived from, for example, softwood or hardwood include chemically treated sulphate, sulfite or soda pulp. In addition, the pulp may also be bleached or unbleached. Preference is given to unbleached pulp, also known as unbleached kraft pulp. The unmilled pulp usually has a freeness of 13-17°ShP, in contrast to coarse and medium pulp having a freeness of 20-40°ShP, and fine pulp having a freeness of 50-60°ShP. Recycled fibers can be obtained, for example, from waste paper. Paper waste can optionally be pre-cleaned of paint. Mixed waste paper typically has a freeness of about 40°ShR, in contrast to deinked waste paper having a freeness of about 60°ShP. Recycled fibers obtained from recycled paper can be used alone or mixed with others, especially natural fibres.

The preferred process is one in which the aqueous suspension of pulp has a degree of freeness, determined by the Schopper-Rigler dewatering kinetics, of 13 to 70°ShF, more preferably 20 to 60°ShF and particularly preferably 30 to 50°ShF.

The first aqueous pulp suspension can be obtained by processing existing paper or cardboard, for example, by mechanical processing of waste paper in a pulper together with water until the desired consistency of the aqueous pulp suspension is achieved. Another example of combining fibers from two sources is the mixing of primary pulp slurry with recycled coated paper waste made using primary pulp slurry.

The primary aqueous pulp suspension, in addition to water (a-a) and pulp (a-b), may contain other components that may be specifically added to it, or that may be contained due to the use of waste paper or available paper.

When the dry matter content is from more than 1.5 to 6 wt. %, preferably from 2.0 to 4.0 wt. %, based on the weight of the first aqueous pulp suspension (corresponding to a pulp concentration of more than about 15 to 60 g/l if substantially only pulp is contained), the mixture is called a thick mass. In the context of the present invention, it should be noted that the difference is that when the dry matter content is from 0.1 to 1.5 wt. %, preferably from 0.3 to 1.4 wt. %, based on the weight of the aqueous pulp suspension (corresponding to a pulp concentration of about 1 to 15 g/l if substantially only pulp is contained), the mixture is commonly referred to as a slurry. The solids content or dry weight of the aqueous pulp suspension means the content of all components that are non-volatile or preferably non-volatile when determining the solids content, carried out by drying at 105°C to constant weight.

Preferably, if the solids content in the first aqueous pulp suspension is from 0.11 to 5 wt. %, more preferably from 0.12 to 4 wt. %), particularly preferably from 0.13 to 3 wt. %, 2 wt. %, 1 wt. %, 0.6 wt. % or 0.35 wt. %, which is the upper limit value, and most preferably from 0.14 to 0.30 wt. %.

Preferably, if in step (A) the polymer P is added to the first pulp slurry, in which the solids content is from more than 1.5 to up to 6.0 wt. %. More preferably, if the resulting second pulp suspension containing polymer P is then diluted to provide a solids content of from 0.1 to 1.5 wt. %. Preferably, if in step (A) the polymer P is added to the first pulp suspension, in which the solids content is from 0.1 to 1.5 wt. %).

After polymer P has been added to the first pulp suspension, it is preferable to wait with the dewatering carried out in step (B) for 0.5 seconds to 2 hours, more preferably for 1.0 seconds to 15 minutes and particularly preferably for 2 to 20 minutes. With. This provides the necessary reaction time for the polymer P.

Preferred is a method in which the amount of added polymer P is from 0.01 to 6.0 wt. % in terms of solids content in the first aqueous pulp suspension. The amount of polymer means the solids content of the polymer. More preferably, if the amount is from 0.02 to 5.0 wt. %, particularly preferably from 0.03 to 1.0 wt. %), more preferably from 0.04 to 0.8 wt. %, more preferably from 0.06 to 0.6 wt. % and most preferably from 0.1 to 0.5 wt. %).

Polymer P is soluble in water if its solubility in water under normal conditions (20° C., 1013 mbar) and a pH value of 7.0 is at least 5% by weight. %, preferably not less than 10 wt. %. The values expressed in mass percent refer to the values for the solids content of the polymer P. The solids content of the polymer P is determined after it has been obtained as an aqueous polymer solution. A sample of the polymer solution in the metal cap is dried in a convection dryer at 140° C. for 120 minutes. Drying is carried out at ambient pressure, possibly at 101.32 kPa, without correcting for any deviation due to weather conditions or altitude.

The precursor of polymer P is the non-hydrolysed polymer V, which is obtained by radical polymerization of monomers (i), (ii), (iii) and optionally (iv).

For the polymerization of monomers (i), (ii), (iii) and optionally (iv) to obtain polymer V, solution, precipitation, suspension or emulsion polymerization is suitable. Solution polymerization carried out in aqueous media is preferred. Suitable aqueous media are water and mixtures of water and at least one water-miscible solvent, for example an alcohol. Examples of alcohols are methanol, ethanol, n-propanol, ethylene glycol or propylene glycol. The polymerization is carried out by means of radicals, for example using radical polymerization initiators, for example peroxides, hydroperoxides, so-called redox catalysts or azo compounds, which decompose to form radicals. Examples of peroxides are alkali metal or ammonium peroxosulfates, diacetyl peroxide, dibenzoyl peroxide, succinyl peroxide, di-tert-butyl peroxide, tert-butylperbenzoate, tert-butylperpivalate, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxy-2-ethylhexanoate, butyl permaleate, cumene hydroperoxide, diisopropyl peroxydicarbamate, bis(o-toluoyl) peroxide, didecanoyl peroxide, dioctanoyl peroxide, dilauroyl peroxide, t-butyl perisobutyrate, t-butyl peracetate or di-t-amyl peroxide. An example of a hydroperoxide is tert-butyl hydroperoxide. Examples of azo compounds which decompose to form radicals are azo-bis-isobutyronitrile, azo-bis-(2-amidonopropane) dihydrochloride or 2-2'-azo-bis-(2-methylbutyronitrile). Examples of so-called redox catalysts are ascorbic acid/iron(II) sulfate/sodium peroxodisulfate, tert-butyl hydroperoxide/sodium disulfite, tert-butyl hydroperoxide/sodium hydroxymethanesulfinate or H ₂ O ₂ /CuI.

The polymerization is carried out, for example, in water or in a mixture containing water as a solvent, at a temperature in the range from 30 to 150°C, preferably from 40 to 110°C, and the reaction can be carried out at ambient pressure, at reduced or increased pressure. For solution polymerization, a water-soluble polymerization initiator is selected, for example 2,2'-azobis(2-methylpropionamidine)dihydrochloride.

When polymerizing monomers (i), (ii), (iii) and optionally (iv) to form polymer V, polymerization regulators can be added to the reaction mixture. Typically, amounts ranging from 0.001 to 5 mol. % in terms of the total amount of all monomers (i), (ii), (iii) and (iv). Polymerization regulators are well known in the literature and are, for example, sulfur compounds, sodium hypophosphite, formic acid or tribromochloromethane. Some examples of sulfur compounds are mercaptoethanol, 2-ethylhexylthioglycolate, thioglycolic acid and dodecylmercaptan.

Preferably, polymer V has a weight average molecular weight Mw of 75,000 to 5,000,000 Da. More preferably, polymer P has a weight average molecular weight Mw of 100,000 to 4,500,000 Da, particularly preferably 180,000 to 2,500,000 Da, and most preferably 210,000 to 1,500,000 Da. The weight average molecular weight can be determined using static light scattering, for example, at a pH value of 9.0 in 1000 mm salt solution.

Examples of monomers (i) of formula I are N-vinylformamide (R ¹ =H), N-vinylacetamide (R ¹ =C ₁ -alkyl), N-vinylpropionamide (R ¹ =C ₂ -alkyl) and N-vinyl butyramide (R ¹ =C ₃ -alkyl). C ₃ -C ₆ Alkyls may be linear or branched. An example of C ₁ -C ₆ -alkyl is methyl, ethyl, n-propyl, 1-methylethyl, n-butyl, 2-methylpropyl, 3-methylpropyl, 1,1-dimethylethyl, n-pentyl, 2-methylbutyl, 3-methylbutyl , 2,2-dimethylpropyl or n-hexyl. R ¹ is preferably H or C ₁ -C ₄ -alkyl, more preferably H or C ₁ -C ₂ -alkyl, more preferably H or C ₁ -alkyl, particularly preferably H, ie. monomer (i) is N-vinylformamide. Although one monomer of formula I may be the only one, the scope of the present invention also includes a mixture of different monomers of formula I used as monomer (i). Preferably, if the proportion of the monomer in which R ¹ =H in the total amount of all monomers (i) of formula I is from 85 to 100%, more preferably from 90 to 100%, particularly preferably from 95 to 100% and most preferably from 99 up to 100%.

Preferably, if the total amount of all monomers (i) is from 33 to 65 mol. % in terms of the amount of all monomers polymerized to obtain polymer V, i.e. all monomers (i), (ii), (iii) and optionally (iv), more preferably if it is from 34 to 63 mol. %, particularly preferably from 35 to 61 mol. % and most preferably from 37 to 55 mol. %. When the lower limit value for the amount of monomer (i), equal to 34 mol. %, the upper limit value for the amount of monomer (ii) is reduced to equal to 55 mol. % and the upper limit value for the amount of monomer (iii) is reduced to equal to 60 mol. %. At the lower limit value for the amount of monomer (i) equal to 35 and 37 mol. %, the upper limit value for the amount of monomer (ii) is reduced to equal to 54 and 52 mol. %, and the upper limit value for the amount of monomer (iii) is reduced to equal to 59 and 57 mol. % respectively. This principle of adjusting upper limits for amounts of other monomers, while increasing the lower limit for the amount of one monomer, also applies to monomers (ii), (iii) and (iv) with the necessary modifications to satisfy the requirement that the total amount of all monomers ( i), (ii), (iii) and optionally (iv) cannot exceed 100 mol. %.

In the context of the present invention, "ethylenically unsaturated monomer" means a monomer containing at least one C ₂ unit, the carbon atoms of which are connected by a carbon-carbon double bond. In case the only substituents are hydrogen atoms, the monomer is ethylene. In the case of substitution with 3 hydrogen atoms, a vinyl derivative is present. In the case of substitution with 2 hydrogen atoms, the E/Z isomer or ethene-1,1-diyl derivative is contained. In the context of the present invention, "monoethylenically unsaturated monomer" means a monomer that contains exactly one C ₂ unit.

If a certain molecule or class of molecules contains a cationic group, then its salt means that the corresponding anion provides a neutral charge. Such anions are, for example, chloride, bromide, hydrogen sulfate, sulfate, hydrogen phosphate, methyl sulfate, acetate or formate. Preferred anions are chloride and hydrogen sulfate, with chloride being particularly preferred. If a certain molecule or class of molecules contains an anionic group, then its salt means that the corresponding cation provides a neutral charge. Such cations are, for example, cations of alkali metals, alkaline earth metals, ammonia, alkylamines or alkanolamines. Preferred are Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ or NH ₄ ⁺ . Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ or NH ₄ ⁺ are more preferred, Na ⁺ , K ⁺ , Ca ²⁺ or NH ₄ ⁺ are especially preferred, Na ⁺ , K ⁺ or NH ₄ ⁺ , Na ⁺ or K ⁺ is more preferred, and Na ⁺ is most preferred.

The monomer (ii) also includes a mixture of individual monomers belonging to the group of monomers (ii).

Examples of the monomer (ii) which is a salt of a monoethylenically unsaturated monomer containing a quaternized nitrogen atom being the only charged group at a pH of 7 are N-alkyl-N'-vinylimidazolium salt, N-alkylated vinylpyridinium salt, acrylamidoalkyltrialkylammonium salt or methacrylamidoalkyltrialkylammonium. For example, the N-alkyl-N'-vinylimidazolium salt is 1-methyl-3-vinylimidazol-1-ium chloride, 1-methyl-3-vinylimidazol-1-ium methyl sulfate or 1-ethyl-3-vinylimidazol-1-ium chloride. For example, the N-alkylated vinylpyridinium salt is 1-methyl-4-vinylpyridin-1-dium chloride, 1-methyl-3-vinylpyridin-1-dium chloride, 1-methyl-2-vinylpyridin-1-dium chloride, or 1-ethyl- 4-vinylpyridin-1-dium chloride. So, for example, the acrylamide-alkyltrialkylammonium salt is acrylamidoethyltrimethylammonium chloride (trimethyl-[2-(prop-2-enoylamino)ethyl]ammonium chloride), acrylamidoethyldiethylmethylammonium chloride (diethylmethyl-[3-(prop-2-enoylamino)ethyl]ammonium chloride), acrylamidopropyltrimethylammonium chloride (trimethyl-[ 3-(prop-2-enoylamino)propyl]ammonium chloride) or acrylamidopropyldiethylmethylammonium chloride (diethylmethyl-[3-(prop-2-enoylamino)propyl]ammonium chloride). For example, the methacrylamidoalkyltrialkylammonium salt is methacrylamidoethyltrimethylammonium chloride (trimethyl-[2-(2-methylprop-2-enoylamino)ethyl]ammonium chloride), methacrylamidoethyldiethylmethylammonium chloride (diethylmethyl-[3-(2-methylprop-2-enoylamino)ethyl]ammonium chloride), methacrylamidopropyltrimethylammonium chloride (trimethyl-[3-(2-methylprop-2-enoylamino)propyl]ammonium chloride) or methacrylamidopropyldiethylmethylammonium chloride (diethylmethyl-[3-(2-methylprop-2-enoylamino)propyl]ammonium chloride).

Preferably, a salt of a monoethylenically unsaturated monomer containing a quaternized nitrogen atom, which is the only charged group at a pH value of 7, is obtained by reaction with a quaternizing reagent, where the quaternizing reagent is dimethyl sulfate, diethyl sulfate, methyl chloride, ethyl chloride or benzyl chloride. Especially preferred is methyl chloride.

Preferably, monomer (ii) is diallyldimethylammonium chloride, diallyldiethylammonium chloride, N-alkyl-N'-vinylimidazolium salt, N-alkylated vinylpyridinium salt, acrylamidoalkyltrialkylammonium salt or methacrylamidoalkyltrialkylammonium salt. More preferred are diallyldimethylammonium chloride, diallyldiethylammonium chloride, N-alkyl-N'-vinylimidazolium salt, acrylamidoalkyltrialkylammonium salt or methacrylamidoalkyltrialkylammonium salt. Especially preferred are diallyldimethylammonium chloride, diallyldiethylammonium chloride, N-alkyl-N'-vinylimidazolium salt, acrylamidoethyltrimethylammonium chloride or acrylamidepropyltrimethylammonium chloride. More preferred are diallyldimethylammonium chloride, diallyldiethylammonium chloride, acrylamidoethyltrimethylammonium chloride or acrylamidopropyltrimethylammonium chloride. Most preferred is diallyldimethylammonium chloride.

Preferably, if the total amount of all monomers (ii) is from 6 to 45 mol. % in terms of the amount of all monomers polymerized to obtain polymer V, i.e. all monomers (i), (ii), (iii) and optionally (iv), more preferably, if it is from 8 to 42 mol. % and especially preferably from 10 to 40 mol. %, most preferably from 10 to 35 mol. %. When the lower limit value for the amount of monomer (ii), equal to 8 or 10 mol. %, the upper limit value for the amount of monomer (i) is reduced to equal to 81 or 79 mol. % and the upper limit value for the amount of monomer (iii) is reduced to equal to 59 or 57 mol. %.

The monomer (iii) also includes a mixture of individual monomers belonging to the group of monomers (iii).

Examples of the monomer (iii), which is a monoethylenically unsaturated carboxylic acid or a salt thereof, are monoethylenically unsaturated C ₃ -C ₈ mono or dicarboxylic acids or salts thereof. Examples are acrylic acid, sodium acrylate, methacrylic acid, sodium methacrylate, dimethacrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, mesaconic acid, citraconic acid, methylenemalonic acid, allylacetic acid, vinylacetic acid or crotonic acid.

Examples of the monomer (iii), which is monoethylenically unsaturated sulfonic acid or a salt thereof, are vinyl sulfonic acid, acrylamide-2-methylpropane sulfonic acid, methacrylamido-2-methylpropane sulfonic acid, allyl sulfonic acid, metallyl sulfonic acid, sulfoethyl acrylate, sulfoethyl methacrylate, sulfopropyl acrylate, sulfopropyl methacrylate, 2-hydroxy -3-methacryloxypropylsulfonic acid or styrenesulfonic acid.

Examples of the monomer (iii), which is monoethylenically unsaturated phosphonic acid or a salt thereof, are vinylphosphonic acid, vinylphosphonic acid monomethyl ester, allylphosphonic acid, allylphosphonic acid monomethylester, acrylamidomethylpropylphosphonic acid or acrylamidomethylenephosphonic acid.

Preferably, the monomer (iii) is a monoethylenically unsaturated C ₃ -C ₈ mono or dicarboxylic acid, a monoethylenically unsaturated sulfonic acid or vinylphosphonic acid, or a salt thereof. More preferably, monomer (iii) is monoethylenically unsaturated C ₃ -C ₈ mono or dicarboxylic acid, acrylamide-2-methylpropanesulfonic acid, methacrylamido-2-methylpropanesulfonic acid or vinylphosphonic acid, or salts thereof. Particular preference is given to monoethylenically unsaturated C ₃ -C ₈ mono or dicarboxylic acid or a salt thereof. More preferred are acrylic acid, methacrylic acid, acrylamide-2-methylpropanesulfonic acid or vinylphosphonic acid, or salts thereof. Especially preferred are acrylic acid or methacrylic acid, or salts thereof. Most preferred are acrylic acid, sodium acrylate, methacrylic acid or sodium methacrylate.

Preferably, if the total amount of all monomers (iii) is from 11 to 40 mol. % in terms of the amount of all monomers polymerized to obtain polymer V, i.e. all monomers (i), (ii), (iii) and optionally (iv), more preferably if it is from 15 to 35 mol. %, particularly preferably from 18 to 33 mol. % and most preferably from 20 to 30 mol. %. When the lower limit value for the amount of monomer (iii), equal to 15, 18 and 20 mol. %, the upper limit value for the amount of monomer (i) is reduced to equal to 79, 76 and 74 mol. %, respectively, and the upper limit value for the amount of monomer (ii) is reduced to equal to 52, 49 and 47 mol. % respectively.

The monomer (iv) also includes a mixture of individual monomers belonging to the group of monomers (iv).

Preferably, if the total amount of all monomers (iv) is from 0 to 30 mol. % in terms of the amount of all monomers polymerized to obtain polymer V, i.e. all monomers (i), (ii), (iii) and optionally (iv), more preferably if it is from 0 to 20 mol. %, particularly preferably from 0.001 to 15 mol. %, more preferably from 0.01 to 10 mol. % and most preferably from 0.015 to 5 mol. %.

The monomers (iv) are ethylenically unsaturated, different from the monomers (i), (ii) and (iii) and are preferably selected from among the following: (iv-1) a mono-ethylenically unsaturated monomer which has no charge at a pH value of 7, or an ethylenically unsaturated monomer , which has no charge at pH 7 and contains exactly two conjugated ethylene double bonds,

(iv-2) a monoethylenically unsaturated monomer which contains at least one secondary or tertiary amino group, and in which that at least one secondary or tertiary amino group is protonated at a pH value of 7, but which does not contain a group that is deprotonated at a pH value of 7, or a diallyl-substituted amine which contains exactly two ethylene double bonds and is quaternized or protonated at a pH value of 7, or a salt thereof,

(iv-3) 0 to 2 mol. % monomer that contains at least two ethylenically unsaturated double bonds that are not conjugated and that is different from a diallyl-substituted amine that contains exactly two ethylene double bonds,

(iv-4) an ethylenically unsaturated monomer which is also different from the monomers (iv-1), (iv-2) and (iv-3),

where the total amount of all monomers (i), (ii), (iii) and (iv-1)-(iv-4) is 100 mol. % and expressed in mol. % amount means the total amount of all monomers (i), (ii), (iii) and (iv-1)-(iv-4).

The monomer (iv-1) also includes a mixture of individual monomers belonging to the group of monomers (iv-1).

Examples of monomers (iv-1) are monoesters of α,β-ethylenically unsaturated monocarboxylic acids formed with C ₁ -C ₃₀ -alkanols, monoesters of α,β-ethylenically unsaturated monocarboxylic acids formed with C ₂ -C ₃₀ -alkanediols, diesters α,β -ethylenically unsaturated dicarboxylic acids formed with C ₁ -C ₃₀ -alkanols or C ₂ -C ₃₀ -alkanediols, primary amides of α,β-ethylenically unsaturated monocarboxylic acids, N-alkylamides of α,β-ethylenically unsaturated monocarboxylic acids, N,N-dialkylamides α ,β-ethylenically unsaturated monocarboxylic acids, nitriles of α,β-ethylenically unsaturated monocarboxylic acids, dinitriles of α,β-ethylenically unsaturated dicarboxylic acids, esters formed from vinyl alcohol with C ₁ -C ₃₀ -monocarboxylic acids, esters formed from allyl alcohol with C ₁ -C ₃₀ -monocarboxylic acids, N-vinyl lactams, nitrogen-free heterocycles containing α,β-ethylenically unsaturated double bond, vinyl aromatic compounds, vinyl halides, vinylidene halides, C ₂ -C ₈ -monoolefins or C ₄ -C ₁₀ -olefins containing exactly two ethylene double bonds that are conjugated.

Monoesters of α,β-ethylenically unsaturated monocarboxylic acids formed with C ₁ -C ₃₀ -alkanols are, for example, methyl acrylate, methyl methacrylate, methyl ethacrylate (= methyl-2-ethyl acrylate), ethyl acrylate, ethyl methacrylate, ethyl ethacrylate (= ethyl-2-ethyl acrylate) , n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, tert-butyl ethacrylate, n-octyl acrylate, n-octyl methacrylate, 1,1,3,3-tetramethylbutyl acrylate, 1,1,3,3 -tetramethylbutyl methacrylate or 2-ethylhexyl acrylate.

Monoesters of α,β-ethylenically unsaturated monocarboxylic acids formed with C ₂ -C ₃₀ -alkanediols are, for example, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl ethacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate , 3-hydroxybutyl acrylate, 3-hydroxybutyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 6-hydroxyhexyl acrylate, or 6-hydroxyhexyl methacrylate.

Primary amides of α,β-ethylenically unsaturated monocarboxylic acids are, for example, acrylic acid amide or methacrylic acid amide.

N-Alkylamides of α,β-ethylenically unsaturated monocarboxylic acids are, for example, N-methylacrylamide, N-methylmethacrylamide, N-isopropylacrylamide, N-isopropylmethacrylamide, N-ethylacrylamide, N-ethylmethacrylamide, N-(n-propyl)acrylamide, N-( n-propyl)methacrylamide, N-(n-butyl)acrylamide, N-(n-butyl)methacrylamide, N-(tert-butyl)acrylamide, N-(tert-butyl)methacrylamide, N-(n-octyl)acrylamide , N-(n-octyl)methacrylamide, N-(1,1,3,3-tetramethylbutyl)acrylamide, N-(1,1,3,3-tetramethylbutyl)methacrylamide, N-(2-ethylhexyl)acrylamide or N -(2-ethylhexylmethacrylamide.

N,N-dialkylamides of α,β-ethylenically unsaturated monocarboxylic acids are, for example, N,N-dimethylacrylamide or N,N-dimethylmethacrylamide.

Nitriles of α,β-ethylenically unsaturated monocarboxylic acids are, for example, acrylonitrile and methacrylonitrile.

Esters derived from vinyl alcohol with C ₁ -C ₃₀ monocarboxylic acids are, for example, vinyl formate, vinyl acetate or vinyl propionate.

N-vinyl lactams are, for example, N-vinylpyrrolidone, N-vinylpiperidone, N-vinylcaprolactam, N-vinyl-5-methyl-2-pyrrolidone, N-vinyl-5-ethyl-2-pyrrolidone, N-vinyl-6-methyl -2-piperidone, N-vinyl-6-ethyl-2-piperidone, N-vinyl-7-methyl-2-caprolactam or N-vinyl-7-ethyl-2-caprolactam.

Vinyl aromatic compounds are, for example, styrene or methylstyrene. Vinyl halides are, for example, vinyl chloride or vinyl fluoride. Vinylidene halides are, for example, vinylidene chloride or vinylidene fluoride. C ₂ -C ₈ monoolefins are, for example, ethylene, propylene, isobutylene, 1-butene, 1-hexene or 1-octene. C ₄ -C ₁₀ -olefins containing exactly two ethylene double bonds that are conjugated are, for example, butadiene or isoprene.

The monomer (iv-1) is preferably acrylonitrile, methacrylonitrile, N-vinylpyrrolidone or vinyl acetate, more preferably acrylonitrile, N-vinylpyrrolidone or vinyl acetate.

Preferably, if the total amount of monomers (iv-1) is from 0 to 30 mol. % in terms of the amount of all monomers polymerized to obtain polymer V, i.e. all monomers (i), (ii), (iii), (iv-1), (iv-2), (iv-3) and (iv-4), more preferably if it is from 0 to 20 mol. %, particularly preferably from 0.001 to 15 mol. %, more preferably from 0.01 to 10 mol. % and most preferably from 0.015 to 5 mol. %.

Monomer (iv-2) also includes a mixture of individual monomers belonging to the group of monomers (iv-2).

Examples of the monomer (iv-2) which is a monoethylenically unsaturated monomer which contains at least one secondary or tertiary amino group, and in which the at least one secondary or tertiary amino group is protonated at a pH value of 7, but which does not contain a group , which is deprotonated at a pH value of 7, or a salt thereof, are esters of α,β-ethylenically unsaturated monocarboxylic acids formed with amino alcohols, mono- and diesters of α,β-ethylenically unsaturated dicarboxylic acids formed with amino alcohols, amides α,β- ethylenically unsaturated monocarboxylic acids formed with dialkylated diamines, N-vinylimidazole or vinylpyridine.

The acid component of the α,β-ethylenically unsaturated monocarboxylic acid esters formed with amino alcohols is preferably acrylic acid or methacrylic acid. Amino alcohols, preferably C ₂ -C ₁₂ -amino alcohols, can be monoalkylated with C ₁ -C ₈ or dialkylated with C ₁ -C ₈ at the amino nitrogen atom. Examples are dialkylaminoethyl acrylates, dialkylaminoethyl methacrylates, dialkylaminopropyl acrylates or dialkylaminopropyl methacrylates. Some examples are N-methylaminoethyl acrylate, N-methylaminoethyl methacrylate, N,N-dimethylaminoethyl acrylate, N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl acrylate, N,N-diethylaminoethyl methacrylate, N,N-dimethylaminopropyl acrylate, N,N-dimethylaminopropyl methacrylate, N,N -diethylaminopropyl acrylate, N,N-diethylaminopropyl methacrylate, N,N-dimethylaminocyclohexyl acrylate or N,N-dimethylaminocyclohexyl methacrylate.

The acid component of the mono- and diesters of α,β-ethylenically unsaturated dicarboxylic acids formed with amino alcohols is preferably fumaric acid, maleic acid, monobutyl maleate, itaconic acid or crotonic acid. Amino alcohols, preferably C ₂ -C ₁₂ -amino alcohols, can be monoalkylated with C ₁ -C ₈ or dialkylated with C ₁ -C ₈ at the amino nitrogen atom.

Amides, α,β-ethylenically unsaturated monocarboxylic acids formed with dialkylated diamines are, for example, dialkylaminoethylacrylamides, dialkylaminoethylmethacrylamides, dialkylaminopropylacrylamides or dialkylaminopropylmethacrylamides. Some examples are N-[2-(dimethylamino)ethyl]acrylamide, N-[2-(dimethylamino)ethyl]methacrylamide, N-[3-(dimethylamino)propyl]acrylamide, N-[3-(dimethylamino)propyl]methacrylamide , N-[4-(dimethylamino)butyl]acrylamide, N-[4-(dimethylamino)butyl]methacrylamide, N-[2-(diethylamino)ethyl]acrylamide, or N-[2-(diethylamino)ethyl]methacrylamide

Examples of the monomer (iv-2) which is a diallyl-substituted amine which contains exactly two ethylene double bonds and is quaternized or protonated at a pH of 7, or a salt thereof, are diallylamine, methyldiallylamine, diallyldipropylammonium chloride or diallyldibutylammonium chloride.

The monomer (iv-2) is preferably N-vinylimidazole.

Preferably, if the total amount of monomers (iv-2) is from 0 to 30 mol. % in terms of the amount of all monomers polymerized to obtain polymer V, i.e. all monomers (i), (ii), (iii), (iv-1), (iv-2), (iv-3) and (iv-4), more preferably if it is from 0 to 20 mol. %, particularly preferably from 0.001 to 15 mol. %, more preferably from 0.01 to 10 mol. % and most preferably from 0.015 to 5 mol. %.

Monomer (iv-3) also includes a mixture of individual monomers belonging to the group of monomers (iv-3).

Examples of monomers (IV-3) are tetraallamonium chloride, trialallamine, methylenebisacrilamide, glycoldiacrylate, glycoldomethacrylate, glycerinthriallate, simple pentaritritritritallic ether, n, n-sh-ethriralmocyarmony chloride, polyalialcoli, everallycoli, everalics. at least twice twice with acrylic acid and/or methacrylic acid, or polyol such as pentaerythritol, sorbitol and glucose.

The monomer (iv-3) is preferably tetraallylammonium chloride.

Monomer (iv-4) also includes a mixture of individual monomers belonging to the group of monomers (iv-3).

The monomers (iv-3) act as crosslinkers. Preferably, if the amount used is from 0.001 to 1 mol. % in terms of the amount of all monomers polymerized to obtain polymer V, i.e. all monomers (i), (ii), (iii), (iv-1), (iv-2), (iv-3) and (iv-4), more preferably if it is from 0.01 to 0 .5 mol. % and particularly preferably from 0.015 to 0.1 mol. %.

Examples of the monomer (iv-4) are sulfobetaine-3-(dimethyl(methacryloylethyl)ammonium)propanesulfonate, sulfobetaine-3-(2-methyl-5-vinylpyridine)propanesulfonate, carboxybetaine-N-3-methacrylamidopropyl-]M^-dimethyl- beta-ammonium propionate, carboxybetaine-N-2-acrylamidoethyl-N,N-dimethyl-beta-ammonium propionate, 3-vinylimidazole-N-oxide, 2-vinylpyridine-N-oxide or 4-vinylpyridine-N-oxide.

Preferably, if the total amount of monomers (iv-4) is from 0 to 30 mol. % in terms of the amount of all monomers polymerized to obtain polymer V, i.e. all monomers (i), (ii), (iii), (iv-1), (iv-2), (iv-3) and (iv-4), more preferably if it is from 0 to 20 mol. %, particularly preferably from 0.001 to 15 mol. %, more preferably from 0.01 to 10 mol. % and most preferably from 0.015 to 5 mol. %.

The monomer (iv) is preferably acrylonitrile, vinyl acetate, N-vinylpyrrolidone or N-vinylimidazole.

Preferably, the polymer V has a weight average molecular weight Mw of 10,000 to 10,000,000 Da. More preferably, polymer P has a weight average molecular weight Mw of 20,000 to 5,000,000 Da, particularly preferably 100,000 to 4,500,000 Da, more preferably 180,000 to 2,400,000 Da and most preferably 210,000 to 1,500,000 Da. The weight average molecular weight can be determined using static light scattering, for example, at a pH value of 9.0 in 1000 mm salt solution.

Preferred is polymer V, which can be obtained by - radical polymerization

(i) from 33 to 83 mol. % monomer of formula I

in which R ¹ =H or C ₁ -C ₆ -alkyl,

(ii) from 6 to 56 mol. % diallyldimethylammonium chloride, diallyldiethylammonium chloride, N-alkyl-N'-vinylimidazolium salt, N-alkylated vinylpyridinium salt, acrylamidoalkyltrialkylammonium salt or methacrylamidoalkyltrialkylammonium salt,

(iii) from 11 to 61 mol. % monoethylenically unsaturated carboxylic acid, monoethylenically unsaturated sulfonic acid or their salts,

(iv) 0 to 50 mol. % of one or more ethylenically unsaturated monomers other than the monomer (i), (ii) and (iii),

where the total amount of all monomers (i), (ii), (iii) and (iv) is 100 mol. %.

Polymer V is preferred, which can be obtained by

- radical polymerization

(i) from 33 to 83 mol. % monomer of formula I

in which R ¹ \u003d H,

(ii) from 6 to 56 mol. % diallyldimethylammonium chloride, N-alkyl-N'-vinylimidazolium salt, acrylamidoalkyltrialkylammonium salt or methacrylamidoalkyltrialkylammonium salt,

(iii) from 11 to 61 mol. % acrylic acid, methacrylic acid, acrylamide-2-methylpropanesulfonic acid or their salts,

(iv) 0 to 50 mol. % of one or more ethylenically unsaturated monomers other than the monomer (i), (ii) and (iii),

where the total amount of all monomers (i), (ii), (iii) and (iv) is 100 mol. %.

Polymer V is preferred, which can be obtained by

- radical polymerization

(i) from 33 to 83 mol. % monomer of formula I

in which R ¹ \u003d H,

(ii) from 6 to 56 mol. % diallyldimethylammonium chloride, N-alkyl-N'-vinylimidazolium salt, acrylamidoalkyltrialkylammonium salt or methacrylamidoalkyltrialkylammonium salt,

(iii) from 11 to 61 mol. % acrylic acid, methacrylic acid, acrylamide-2-methylpropanesulfonic acid or their salts,

(iv) 0 to 50 mol. % acrylonitrile, vinyl acetate, N-vinylpyrrolidone or N-vinylimidazole,

where the total amount of all monomers (i), (ii), (iii) and (iv) is 100 mol. %.

Polymer V is preferred, which can be obtained by

- radical polymerization

(i) from 33 to 83 mol. % monomer of formula I

in which R ¹ \u003d H,

(ii) from 6 to 56 mol. % diallyldimethylammonium chloride, N-alkyl-N'-vinylimidazolium salt or acrylamidopropyltrimethylammonium chloride,

(iii) from 11 to 61 mol. % acrylic acid, methacrylic acid, acrylamide-2-methylpropanesulfonic acid or their salts,

(iv) 0 to 50 mol. % of one or more ethylenically unsaturated monomers other than the monomer (i), (ii) and (iii),

where the total amount of all monomers (i), (ii), (iii) and (iv) is 100 mol. %.

Polymer V is preferred, which can be obtained by

- radical polymerization f

(i) from 33 to 83 mol. % monomer of formula I

in which R ¹ \u003d H,

(ii) from 6 to 56 mol. % diallyldimethylammonium chloride, N-alkyl-N'-vinylimidazolium salt or acrylamidopropyltrimethylammonium chloride,

(iii) from 11 to 61 mol. % acrylic acid, methacrylic acid, acrylamide-2-methylpropanesulfonic acid or their salts,

(iv) 0 to 50 mol. % acrylonitrile, vinyl acetate, N-vinylpyrrolidone or N-vinylimidazole,

where the total amount of all monomers (i), (ii), (iii) and (iv) is 100 mol. %.

Polymer V is preferred, which can be obtained by

- radical polymerization

(i) from 33 to 83 mol. % monomer of formula I

in which R ¹ \u003d H,

(ii) from 6 to 56 mol. % diallyldimethylammonium chloride,

(iii) from 11 to 61 mol. mol % % acrylic acid or methacrylic acid, or their salts,

(iv) 0 to 50 mol. % of one or more ethylenically unsaturated monomers other than the monomer (i), (ii) and (iii),

where the total amount of all monomers (i), (ii), (iii) and (iv) is 100 mol. %.

Polymer V is preferred, which can be obtained by

- radical polymerization

(i) from 33 to 83 mol. % monomer of formula I

in which R ¹ \u003d H,

(ii) from 6 to 35 mol. % diallyldimethylammonium chloride,

(iii) from 11 to 61 mol. % acrylic acid or methacrylic acid, or their salts,

(iv) 0 to 50 mol. % of one or more ethylenically unsaturated monomers other than the monomer (i), (ii) and (iii),

where the total amount of all monomers (i), (ii), (iii) and (iv) is 100 mol. %.

Polymer V is preferred, which can be obtained by

- radical polymerization

(i) from 33 to 55 mol. % monomer of formula I

in which R ¹ \u003d H,

(ii) 10 to 40 mol. % diallyldimethylammonium chloride,

(iii) from 11 to 40 mol. % acrylic acid or methacrylic acid, or their salts,

where the total amount of all monomers (i), (ii) and (iii) is 100 mol. %.

Polymer V obtained by polymerization of monomers of formula I comprises polymerized units containing the corresponding amide groups of formula I. In the case of N-vinylformamide, i. in the case of formula I, in which R ¹ =H, it is the formamide group NH-C(=O)H.

Polymer P is obtained by partial or complete hydrolysis of polymer V. As is known, for example, from EP 0438744 A1, pages 8/lines 26-34, the amide group can be hydrolyzed in an acid medium or in an alkaline medium, which leads to the elimination of the carboxylic acid and the formation primary amino group. Preferred is the hydrolysis of the amide group in an alkaline medium. If not all amide groups are hydrolyzed, it is known that a cyclic 6-membered amidine can be formed by condensation of the primary amino group with the adjacent amide group. In this case, hydrolysis of the amide group results in the formation of a primary amino or amidine group in polymer P, according to the reaction scheme below.

In the case of polymerization of ethylene derivatives substituted directly at the ethylene functional group by a cyano group, for example acrylonitrile, polymer V additionally contains cyano groups. It is known that the primary amino group contained in the polymer P, formed as a result of hydrolysis, can react with one of these cyano groups to form a cyclic 5-membered amidine. In this case, hydrolysis of the amide group results in the formation of an amidine group in polymer P, according to the reaction scheme below. In the reaction scheme below, the cyano-substituted ethylene derivative is polymerized acrylonitrile.

In both cases described, the hydrolysis of the amide group contained in the monomer of formula I leads to the formation of a primary amino group or an amidine group. The primary amino group or amidine group has a positive charge at pH=7 and this provides a cationic charge in the polymer P.

Conditions for carrying out the hydrolysis of the amide groups contained in the polymer P, which originate from the monomers of formula I, can also lead to the hydrolysis of other groups contained in the polymer V, which are easily hydrolyzed under these conditions. It is known, for example, from EP 0216387 A2, column 6/lines 7-43, or from WO 2016/001016 A1, pages 17/lines 1-8, that the acetate groups contained in the polymer V, which originate from the vinyl acetate used as copolymerized monomer, (iv-1). Accordingly, a secondary hydroxyl group is formed in polymer P, as shown below.

The number of monomer units of formula (I) polymerized to give polymer V, which is hydrolyzed to give polymer P, can be determined experimentally by determining the amount of HOC(=O)R ¹ carboxylic acids cleaved from NC(=O)R ¹ groups. The number of hydrolysed NC(=O)R ¹ groups contained in the polymerized units of formula I, referred to the amount of all polymerized units of formula I, multiplied by 100%, gives the degree of hydrolysis.

Preferably, at least 87 to 100% of the NC(=O)R ¹ groups contained in the units of the monomers of formula (I) polymerized to obtain polymer V are hydrolyzed, based on the amount of all units of the monomers of formula I polymerized to obtain polymer V. More preferably 88 to 100% hydrolysed, particularly preferably 90 to 99%, more preferably 93 to 98% and most preferably 94 to 97% of these groups.

Preferably, the polymer P is amphoteric-cationic. Polymer P is amphoteric because it includes polymer units containing a functional group that has a positive charge at least at a pH value of 7, for example, polymerized monomers (ii) and hydrolyzed, polymerized monomers (i), and polymer units containing a functional group which has a negative charge at least at a pH value of 7, for example polymerized monomers (iii). If the number of all functional groups with positive charges exceeds the number of all functional groups with negative charges, and the number of positively charged units differs from the number of negatively charged units by 7 mol. % or more units, with 100 mol. % units means the amount of all polymerized monomers used to obtain polymer V, then polymer P is amphoteric-cationic. So, for example, amphoteric-cationic is the polymer P, which is obtained by polymerization of 50 mol. % N-vinylformamide, 7 mol. % DADMAC (diallyldimethylammonium chloride) and 43 mol. % sodium acrylate, and the degree of hydrolysis of the polymerized N-vinylformamide units is 90%. The number of positively charged units is 52 mol. %, the number of negatively charged units is 43 mol. % and the difference is 9 mol. %. More preferably, if the polymer P is amphoteric-cationic and expressed in mol. % the number of positively charged units is less than expressed in mol. % the number of negatively charged units, in terms of the total amount of monomers polymerized to obtain polymer V, and ranges from 20 to 89 mol. %. Particularly preferably, if it is from 30 to 70 mol. % and most preferably from 35 to 60 mol. %.

Preferably, the polymer P has a weight average molecular weight Mw of 8,000 to 8,000,000 Da. More preferably, polymer P has a weight average molecular weight Mw of 16,000 to 4,000,000 Da, particularly preferably 80,000 to 3,600,000 Da, more preferably 150,000 to 2,000,000 Da and most preferably 170,000 to 1,200,000 Da. The weight average molecular weight can be determined using static light scattering, for example, at a pH value of 9.0 in 1000 mm salt solution.

Preferred is polymer P, which can be obtained by radical polymerization proceeding to obtain polymer V

(i) from 33 to 83 mol. % monomer of formula I

in which R ¹ =H or C ₁ -C ₆ -alkyl,

(ii) from 6 to 56 mol. % diallyldimethylammonium chloride, diallyldiethylammonium chloride, N-alkyl-N'-vinylimidazolium salt, N-alkylated vinylpyridinium salt, acrylamidoalkyltrialkylammonium salt or methacrylamidoalkyltrialkylammonium salt,

(iii) from 11 to 61 mol. % monoethylenically unsaturated carboxylic acid, monoethylenically unsaturated sulfonic acid or their salts,

(iv) 0 to 50 mol. % of one or more ethylenically unsaturated monomers other than the monomer (i), (ii) and (iii),

where the total amount of all monomers (i), (ii), (iii) and (iv) is 100 mol. %,

And

- hydrolysis of the NC(=O)R ¹ groups contained in the units of the monomers of formula (I), polymerized to obtain polymer V, with the formation of primary amino groups or amide groups in the polymer P, where at least 87% of the units of the monomers of formula (I) are hydrolyzed , polymerized to obtain polymer V, in terms of the amount of all units of the monomers of formula I, polymerized to obtain polymer V.

The preferred polymer is P, which can be obtained by

- proceeding with obtaining polymer V radical polymerization

(i) from 33 to 83 mol. % monomer of formula I

in which R ¹ \u003d H,

(ii) from 6 to 56 mol. % diallyldimethylammonium chloride, N-alkyl-N'-vinylimidazolium salt, acrylamidoalkyltrialkylammonium salt or methacrylamidoalkyltrialkylammonium salt,

(iii) from 11 to 61 mol. % acrylic acid, methacrylic acid, acrylamide-2-methylpropanesulfonic acid or their salts,

(iv) 0 to 50 mol. % of one or more ethylenically unsaturated monomers other than the monomer (i), (ii) and (iii),

where the total amount of all monomers (i), (ii), (iii) and (iv) is 100 mol. %,

And

- hydrolysis of the NC(=O)R ¹ groups contained in the units of the monomers of formula (I), polymerized to obtain polymer V, with the formation of primary amino groups or amide groups in the polymer P, where at least 87% of the units of the monomers of formula (I) are hydrolyzed , polymerized to obtain polymer V, in terms of the amount of all units of the monomers of formula I, polymerized to obtain polymer V.

The preferred polymer is P, which can be obtained by

- proceeding with obtaining polymer V radical polymerization

(i) from 33 to 83 mol. % monomer of formula I

in which R ¹ \u003d H,

(ii) from 6 to 56 mol. % diallyldimethylammonium chloride, N-alkyl-N'-vinylimidazolium salt, acrylamidoalkyltrialkylammonium salt or methacrylamidoalkyltrialkylammonium salt,

(iii) from 11 to 61 mol. % acrylic acid, methacrylic acid, acrylamide-2-methylpropanesulfonic acid or their salts,

(iv) 0 to 50 mol. % acrylonitrile, vinyl acetate, N-vinylpyrrolidone or N-vinylimidazole,

where the total amount of all monomers (i), (ii), (iii) and (iv) is 100 mol. %,

And

- hydrolysis of the NC(=O)R ¹ groups contained in the units of the monomers of formula (I), polymerized to obtain polymer V, with the formation of primary amino groups or amide groups in the polymer P, where at least 87% of the units of the monomers of formula (I) are hydrolyzed , polymerized to obtain polymer V, in terms of the amount of all units of the monomers of formula I, polymerized to obtain polymer V.

The preferred polymer is P, which can be obtained by

- proceeding with obtaining polymer V radical polymerization

(i) from 33 to 83 mol. % monomer of formula I

in which R ¹ \u003d H,

(ii) from 6 to 56 mol. % diallyldimethylammonium chloride, N-alkyl-N'-vinylimidazolium salt or acrylamidopropyltrimethylammonium chloride,

(iii) from 11 to 61 mol. % acrylic acid, methacrylic acid, acrylamide-2-methylpropanesulfonic acid or their salts,

(iv) 0 to 50 mol. % of one or more ethylenically unsaturated monomers other than the monomer (i), (ii) and (iii),

where the total amount of all monomers (i), (ii), (iii) and (iv) is 100 mol. %,

And

- hydrolysis of the NC(=O)R ¹ groups contained in the units of the monomers of formula (I), polymerized to obtain polymer V, with the formation of primary amino groups or amide groups in the polymer P, where at least 87% of the units of the monomers of formula (I) are hydrolyzed , polymerized to obtain polymer V, in terms of the amount of all units of the monomers of formula I, polymerized to obtain polymer V.

The preferred polymer is P, which can be obtained by

- proceeding with obtaining polymer V radical polymerization

(i) from 33 to 83 mol. % monomer of formula I

in which R ¹ \u003d H,

(ii) from 6 to 56 mol. % diallyldimethylammonium chloride, N-alkyl-N'-vinylimidazolium salt or acrylamidopropyltrimethylammonium chloride,

(iii) from 11 to 61 mol. % acrylic acid, methacrylic acid, acrylamide-2-methylpropanesulfonic acid or their salts,

(iv) 0 to 50 mol. % acrylonitrile, vinyl acetate, N-vinylpyrrolidone or N-vinylimidazole,

where the total amount of all monomers (i), (ii), (iii) and (iv) is 100 mol. %,

And

- hydrolysis of the NC(=O)R ¹ groups contained in the units of the monomers of formula (I), polymerized to obtain polymer V, with the formation of primary amino groups or amide groups in the polymer P, where at least 87% of the units of the monomers of formula (I) are hydrolyzed , polymerized to obtain polymer V, in terms of the amount of all units of the monomers of formula I, polymerized to obtain polymer V.

The preferred polymer is P, which can be obtained by

- proceeding with obtaining polymer V radical polymerization

(i) from 33 to 83 mol. % monomer of formula I

in which R ¹ \u003d H,

(ii) from 6 to 56 mol. % diallyldimethylammonium chloride,

(iii) from 11 to 61 mol. % acrylic acid or methacrylic acid, or their salts,

(iv) 0 to 50 mol. % of one or more ethylenically unsaturated monomers other than the monomer (i), (ii) and (iii),

where the total amount of all monomers (i), (ii), (iii) and (iv) is 100 mol. %,

And

- hydrolysis of the NC(=O)R ¹ groups contained in the units of the monomers of formula (I), polymerized to obtain polymer V, with the formation of primary amino groups or amide groups in the polymer P, where at least 87% of the units of the monomers of formula (I) are hydrolyzed , polymerized to obtain polymer V, in terms of the amount of all units of the monomers of formula I, polymerized to obtain polymer V.

The preferred polymer is P, which can be obtained by

- proceeding with obtaining polymer V radical polymerization

(i) from 33 to 83 mol. % monomer of formula I

in which R ¹ \u003d H,

(ii) from 6 to 35 mol. % diallyldimethylammonium chloride,

(iii) from 11 to 61 mol. % acrylic acid or methacrylic acid, or their salts,

(iv) 0 to 50 mol. % of one or more ethylenically unsaturated monomers other than the monomer (i), (ii) and (iii),

where the total amount of all monomers (i), (ii), (iii) and (iv) is 100 mol. %,

And

- hydrolysis of the NC(=O)R ¹ groups contained in the units of the monomers of formula (I), polymerized to obtain polymer V, with the formation of primary amino groups or amide groups in the polymer P, where at least 87% of the units of the monomers of formula (I) are hydrolyzed , polymerized to obtain polymer V, in terms of the amount of all units of the monomers of formula I, polymerized to obtain polymer V.

The preferred polymer is P, which can be obtained by

- proceeding with obtaining polymer V radical polymerization

(i) from 33 to 55 mol. % monomer of formula I

in which R ¹ \u003d H,

(ii) 10 to 40 mol. % diallyldimethylammonium chloride,

(iii) from 11 to 40 mol. % acrylic acid or methacrylic acid, or their salts,

where the total amount of all monomers (i), (ii) and (iii) is 100 mol. %,

And

- hydrolysis of the NC(=O)R ¹ groups contained in the units of the monomers of formula (I), polymerized to obtain polymer V, with the formation of primary amino groups or amide groups in the polymer P, where at least 87% of the units of the monomers of formula (I) are hydrolyzed , polymerized to obtain polymer V, in terms of the amount of all units of the monomers of formula I, polymerized to obtain polymer V.

The second aqueous pulp suspension containing polymer P includes (a-a) water

(a-b) pulp

(a-c) polymer R.

A possible additional component of the second aqueous pulp suspension is (a-d) an organic polymer different from the pulp and from polymer P. The organic polymer (a-d) may be neutral, cationic or anionic.

The neutral organic polymer (ad) may be uncharged neutral because it does not include polymeric units containing a functional group that has a charge of at least pH 7. In the context of the present invention, "a functional group that has a charge of at least pH A pH of 7" means an atom or a linked group of atoms covalently attached to the rest of the polymer unit. The functional group constantly has a charge or acts on its own, i.e. regardless of the other components of the polymer unit or other polymer units, in its uncharged form in pure water as an acid or as a base. Acting as an acid gives rise to a negative charge on the corresponding functional group of the polymer unit when deprotonated with a base. This can be carried out, for example, with NaOH, KOH or NH ₃ , which are usually used in aqueous solution, and result in the corresponding sodium, potassium or ammonium salts. Acting as a base results in a positive charge on the corresponding functional group of the polymer unit if acid protonation is carried out. This can be carried out, for example, with HCl, H ₂ SO ₄ , H ₃ PO ₄ , HCOOH or H ₃ COOH, which are usually used in aqueous solution, and result in the corresponding chlorides, hydrogen sulfate/sulfates, dihydrophosphates/hydrophosphates/phosphates, formates or acetates. An example of a functional group having a permanent positive charge is -(CH ₂ ) ₄ N ⁺ (tetraalkylated nitrogen atom), such as that found in diallyldimethylammonium or 2-(N,N,N-trimethylammonium)ethyl acrylate. Examples of functional groups, the presence of which leads to the appearance of negative charges in the polymer unit, are -COOH (carboxylic acid group), -SO ₂ OH (sulfonic acid group), PO (OH) ₂ (phosphonic acid group), -O-SO ₂ OH (monoesterified sulfuric acid group) or -O-PO(OH) ₂ (monoesterified phosphoric acid group). Examples of functional groups, the presence of which leads to the appearance of positive charges in the polymer unit, are -CH ₂ -CH (NH ₂ ) - or -CH ₂ -NH ₂ (primary and basic amino group), (-CH ₂ -) ₂ NH (secondary and basic amino group), (-CH ₂ -) ₃ N (tertiary and basic amino group) or (-) ₂ CH-N=CH-NH-CH(-) ₂ (basic amidine group, in particular also in the form of cyclic amidine groups).

Polyacrylamide, acrylamide-acrylonitrile copolymer, poly(vinyl alcohol), or vinyl alcohol-vinyl acetate copolymer are examples of the neutral organic polymer (a-d) without polymer units containing a functional group having a charge of at least pH 7.

The neutral organic polymer (ad) can also be amphoteric-neutral because it includes polymer units containing a functional group that has a negative charge at least at a pH value of 7 and polymer units containing a functional group that has a positive charge at at least at a pH value of 7, and, in addition, in functional groups, the number of all negative charges and the number of all positive charges balance each other. An organic polymer in which the number of positively charged units differs from the number of negatively charged units by less than 7 mol. % links, in the context of the present invention is also considered to be amphoterically neutral, with 100 mol. % units means the amount of all polymerized monomers used to produce an organic polymer. For example, an organic polymer obtained by polymerization of 30 mol. % acrylic acid and 70 mol. % N-vinylformamide, and in which half of the polymerized N-vinylformamide units are then hydrolyzed, with a difference in the amounts of units containing functional groups -COOH and -CH ₂ -CH(NH ₂ )-, component 5 mol. % links, is considered amphoterically neutral. In the case of polymerization 10 mol. % itaconic acid (HOOC-CH ₂ -C(=CH ₂ )-COOH), 10 mol. % acrylic acid and 80 mol. % N-vinylformamide to obtain an organic polymer, in which 44% of polymerized N-vinylformamide units are then hydrolyzed, the polymer is considered amphoterically neutral with a difference in the amounts of units containing functional groups -COOH and -CH ₂ -CH(NH ₂ )-, component 5 they say % links.

The cationic organic polymer (a-d) may be fully cationic, i. it includes polymeric units containing a functional group that is positively charged at at least a pH of 7, but does not include polymeric units containing a functional group that is negatively charged at least at a pH of 7. Examples of a fully cationic The organic polymers (a-d) are poly(allylamine), poly(diallylamine), poly(diallyldimethylammonium chloride), acrylamide-diallyldimethylammonium chloride copolymer or acrylamide-2-N,N,N-trimethylammonium)ethyl acrylate chloride copolymer.

The cationic organic polymer (ad) may also be amphoteric-cationic, ie. it includes polymer units containing a functional group that has a positive charge at least at a pH value of 7, and polymer units containing a functional group that has a negative charge at least at a pH value of 7, and in functional groups the amount of all positive charges exceeds the number of all negative charges. In the context of the present invention, an organic polymer is considered to be amphoteric-cationic, in which the number of positively charged units differs from the number of negatively charged units by 7 mol. % or more units, 100 mol. % units means the amount of all polymerized monomers used to produce an organic polymer. For example, an organic polymer obtained by polymerization of 30 mol. % acrylic acid and 70 mol. % N-vinylformamide, and in which 57% of polymerized N-vinylformamide units are then hydrolyzed, with a difference in the amounts of units containing functional groups -COOH and -CH ₂ -CH(NH ₂ )-, component 10 mol. % links, is considered amphoteric-cationic.

The anionic organic polymer (a-d) may be fully anionic, ie. it includes polymeric units containing a functional group that is negatively charged at at least pH 7, but does not include polymeric units containing a functional group that is positively charged at least at pH 7. Examples of a fully anionic The organic polymers (a-d) are poly(acrylic acid), a copolymer of styrene with n-butyl acrylate and with acrylic acid, or a copolymer of acrylamide with acrylonitrile and with acrylic acid.

The anionic organic polymer (ad) may also be amphoteric-anionic, ie. it includes polymeric units containing a functional group that has a negative charge at least at a pH value of 7, and polymer units containing a functional group that has a positive charge at least at a pH value of 7, and in functional groups the amount of all negative charges exceeds the number of all positive charges. In the context of the present invention, an organic polymer is considered to be amphoteric-anionic, in which the number of negatively charged units differs from the number of positively charged units by 7 mol. % or more units, 100 mol. % units means the amount of all polymerized monomers used to produce an organic polymer. For example, an organic polymer obtained by polymerization of 30 mol. % acrylic acid and 70 mol. % N-vinylformamide, and in which then hydrolyze 29% polymerized N-vinylformamide units, with a difference in the amounts of units containing functional groups -COOH and -CH ₂ -CH(NH ₂ )-, component 10 mol. % links, is considered amphoteric-anionic.

Organic polymers (a-d) can also be divided into linear, branched and cross-linked. Crosslinking can be achieved, for example, by adding a crosslinking agent during the polymerization of the starting monomers, or by adding a crosslinking agent after polymerization is completed, in particular immediately before adding the organic polymer (a-d) to the second aqueous pulp suspension. Thus, for example, polyacrylamide can be crosslinked already during the polymerization by adding a crosslinking agent, methylenebisacrylamide, to the acrylamide, or by adding a crosslinking agent, such as glyoxal, after the polymerization. If necessary, you can combine both methods of stitching. Of particular note is the cross-linked organic polymer, which has a high degree of cross-linking, usually already during the polymerization of the monomers. It is contained in the second aqueous pulp suspension containing polymer P in the form of particles, in particular in the form of so-called organic microparticles.

Organic polymers (a-d) can also be divided into natural, modified natural or synthetic. The natural organic polymer is usually a polymer of natural origin, appropriate isolation steps are carried out if necessary, but no special modifications are carried out by chemical synthesis. An example of a natural organic polymer (a-d) is unmodified starch. Cellulose is not an example of a natural organic polymer (a-d), which is pulp (a-b) in the present invention. The modified natural organic polymer is a polymer modified by chemical synthesis steps. An example of a modified natural organic polymer (a-d) is cationic starch. Synthetic organic polymer (a-d) is obtained by chemical synthesis from individual monomers. An example of a synthetic organic polymer (a-d) is polyacrylamide.

It is preferred that in step (A) the organic polymer (a-d) is added to the first pulp slurry or to the second pulp slurry containing polymer P. More preferably, the organic polymer (a-d), which is a modified natural organic polymer, is added. A particularly preferred organic polymer (a-d) is cationic starch. Most preferably, the cationic starch is the only organic polymer (a-d) which is added in step (A) to the first pulp slurry in addition to polymer P or to the second pulp slurry containing polymer P.

A possible additional component of the aqueous pulp suspension containing polymer P is (a-e) filler. The filler (a-e) is an inorganic particle, in particular an inorganic pigment. Possible inorganic pigments are all pigments based on metal oxides, silicates and/or carbonates, which are usually used in the paper industry, in particular metals, pigments selected from the group consisting of calcium carbonate, which can be used in the form of ground lime, chalk, marble ( RKK (ground calcium carbonate)) or precipitated calcium carbonate (PCC), talc, kaolin, bentonite, satinite, calcium sulfate, barium sulfate and titanium dioxide. Inorganic particles is also a colloidal solution of polysilicic acids, in which the particles of silicon dioxide usually have a size equal to 5 to 150 nm.

In this case, the filler (a-e) also includes two or more different fillers. Accordingly, the filler (a-e) used as a possible additional component of the aqueous pulp suspension is divided into the first filler (a-e-1), the second filler (a-e-2) ... and the like.

Preferably, inorganic pigments having an average particle size (volume average size) of ≦10 µm, more preferably 0.3 to 5 µm, particularly preferably up to 0.5 to 2 µm, are used. Determination of the average particle size (average volume size) of inorganic pigments, as well as particles of a powdered composition in the context of the present invention, is usually carried out according to the method of quasi-elastic light scattering (DIN-ISO 13320-1), for example, using the Mastersizer 2000, manufactured by Malvern Instruments Ltd.

A process is preferred in which, in step (A), filler (a-e) is added to the first pulp slurry or to the second pulp slurry containing polymer P.

Preferably, if the total amount of filler (a-e) is from 0 to 40 wt. % in terms of the weight of the obtained paper or cardboard and in terms of the solids content in the filler (a-e), amounting to 100 wt. %, and the content of solids in paper or cardboard, amounting to 100 wt. %. More preferably, if the total amount of filler (a-e) is from 5 to 30 wt. %, particularly preferably from 15 to 25 wt. % and most preferably from 15 to 20 wt. %.

Preferably, if the resulting paper or board contains filler (a-e) in a total amount of 5 to 30 wt. %. Such paper is, for example, wood-free paper. Preferably, if the resulting paper or paperboard contains filler (a-e) in a total amount of 5 to 20 wt. %. Such paper is mainly used as wrapping paper. Preferably, if the resulting paper or paperboard contains filler (a-e) in a total amount of 5 to 15 wt. %. This paper is mainly used for printing newspapers. Preferably, if the resulting paper or board contains filler (a-e) in a total amount of 25 to 40 wt. %. Such paper is, for example, SC (supercalendered) paper.

Preferably, in step (A), the polymer P is added to the first aqueous pulp suspension prior to the addition of the filler (a-e). It is more preferable to add the polymer P before adding the filler (a-e) and before adding the organic polymer (a-d), except in the case of adding cationic starch. It is particularly preferred to add polymer P to the first aqueous pulp slurry before addition of filler (a-e), before addition of organic polymer (a-d) other than cationic starch, and before addition of any other paper aid (a-f).

In step (A), filler (a-e) is optionally added, preferably to a second pulp slurry containing polymer P, which has a solids content of 0.1 to 1.5 wt. %. This addition corresponds to the so-called addition to the liquid mass. The second pulp suspension containing polymer P is either already available and has this solids content, or it is pre-diluted to provide a solids content of from 0.1 to 1.5 wt. %, based on the content of solids, ranging from more than 0.15 to 6.0 wt. %.

In step (A), filler (a-e) is added if necessary, preferably to the second pulp suspension containing polymer P, the first part of the total amount of filler (a-e) to be added is added to the pulp suspension containing polymer P, which has a solids content of more than 0.15 and up to 6.0 wt. %, and the second part of the total amount of filler (a-e) to be added is added to the pulp suspension containing polymer P, after dilution to ensure a solids content of 0.1 to 1.5 wt. %. It is necessary to add the first part and the second part of the total amount of filler (a-e). The ratio of the mass of the first part to the mass of the second part is from 5 to 0.2.

A possible additional component of the aqueous pulp slurry containing polymer P is (af) another paper additive. Another paper additive (af) is different from the above components (a-b), polymer P using (a-c), (a-d) and (a-e) as a component. Another paper additive (af) is, for example, a bulk sizing agent, a water-soluble salt formed with a ferric metal cation, an antifoam, a non-polymeric wet strength agent, a biocide, an optical brightener or a paper dye. Examples of bulk sizing agents are alkyl chain dimers (ACD), alkenyl succinic anhydrides (ASA) and resin glue. Examples of water-soluble salts formed with a trivalent metal cation are aluminum(III) salts, in particular AlCl ₃ such as AlCl ₃ ⋅6H ₂ O), Al ₂ (SO ₄ ) ₃ such as Al ₂ (SO ₄ ) ₃ ⋅18H ₂ O, or KAl(SO ₄ ) ₂ ⋅12H ₂ O. Other paper auxiliaries (af) can preferably be used in normal amounts.

Preferably, another paper aid (a-f) is added to the second pulp slurry containing polymer P, which has a solids content of 0.1 to 1.5 wt. %. This addition corresponds to the so-called addition to the liquid mass. The second pulp suspension containing polymer P is either already available and has this solids content, or it is pre-diluted to provide a solids content of from 0.1 to 1.5 wt. %, based on the content of solids, ranging from more than 0.15 and up to 6.0 wt. %).

In the context of the present invention, the other paper aid (a-f) also includes two or more different other paper aids. Accordingly, another paper auxiliary additive (a-f) used as a possible additional component of the second aqueous pulp suspension containing polymer P is separated into the first other paper auxiliary additive (a-f-1), the second other paper auxiliary additive (a-f-2 ) … and so on.

During papermaking, more than one organic polymer (a-d) and more than one filler (a-e) are often added to the aqueous pulp suspension. In the case of an organic polymer (a-d), this is done, for example, to influence the performance of the papermaking process itself or the performance of the paper produced. Retaining agents, dewatering agents, wet strength agents, or other dry strength agents are used.

Examples of retention aids are cationic, amphoteric or anionic polymers (a-d). Examples are anionic polyacrylamide, cationic polyacrylamide, cationic starch, cationic polyethyleneimine or cationic polyvinylamine. The retaining agent is, for example, a filler (a-e), which is anionic microparticles, in particular colloidal silicon dioxide or bentonite. Combinations of the above substances are also possible. In particular, one combination is a two-component system containing a cationic polymer and anionic microparticles or an anionic polymer and cationic microparticles. The preferred retention aid is a synthetic organic polymer (a-d) or a two-component system. When used as a retention aid, for example, a two-component system, the cationic first organic polymer (a-d-l) is already contained in combination with the first filler (a-e-1), for example, a suitable bentonite, and then the second filler (a-e -2) is calcium carbonate.

Examples of another dry strength agent are a synthetic organic polymer (a-d) such as polyvinylamine, polyethyleneimine, polyacrylamide or glyoxylated polyacrylamide, a natural organic polymer (a-d) such as unmodified starch, or a modified natural organic polymer (a-d), such as cationically modified starch or oxidatively or enzymatically degraded starch. Preferably, another dry strength agent is added to the first aqueous pulp slurry or to the second aqueous pulp slurry containing polymer P, both of which have a solids content of greater than 1.5 to 6.0 wt. %. You can add to the first aqueous pulp suspension or to the second aqueous pulp suspension containing polymer P, both of which have a solids content of from 0.1 to up to 1.5 wt. %.

Preferably, the second aqueous pulp suspension containing polymer P does not contain so-called microparticles. Organic microparticles are an organic polymer that has limited water solubility and may be crosslinked. Preferably, the organic microparticles are insoluble in water, although it is more preferred if they are water-swellable. In the unswollen state, the organic microparticles have an average diameter of ≦750 nm, preferably ≦500 nm, particularly preferably in the range of 25 to 300 nm. The polymerization of organic microparticles is usually carried out by inverse emulsion polymerization or inverse microemulsion polymerization and is generally known to the person skilled in the art. Such polymerization reactions are described, for example, in US 2003/0192664 (page 6), the description of which is expressly incorporated into the present invention by reference. Microparticles are typically prepared by (a) preparing a W/O (water-in-oil) emulsion containing an oil phase as a continuous phase and an aqueous discontinuous phase by emulsifying an aqueous solution of monomers in a hydrocarbon in the presence of a surfactant, and (b) carrying out free radical polymerization. It is preferred to use anionic organic microparticles, in particular copolymers of acrylamide with one or more anionic monomers. Inorganic microparticles, unlike inorganic fillers, which have a BET specific surface area (Brunauer-Emmett-Teller specific surface area) of ≤20 m ² /g, have a BET specific surface area of ≥100 m ² /g (determination of BET surface values is carried out in accordance with DIN ISO 9277: 2003-05). The inorganic microparticles are preferably bentonite, colloidal silica, silicates and/or calcium carbonate having a wet BET surface of ≥100 m ² /g. Bentonite generally means phyllosilicates which swell in water. These are mainly the clay mineral montmorillonite and similar clay minerals such as nontronite, hectorite, saponite, sauconite, beidellite, allewardite, illite, halloysite, attapulgite and sepiolite. These phyllosilicates are preferably activated prior to use, ie. converted to a water-swellable form by treating the phyllosilicates with an aqueous solution of a base, such as aqueous solutions of caustic soda, potassium hydroxide, sodium hydroxide, or potassium carbonate. They have a specific surface area of 200-1000 m ² /g and an average particle size distribution of 1-250 nm, typically in the range of 40-100 nm. The possibility of using microparticles can be an advantage of the method proposed in the present invention.

In step (B), a second aqueous pulp slurry containing polymer P is applied to a water-permeable substrate. The water-permeable substrate includes a top and bottom side and fine holes that allow water to flow through but generally prevent fibrous components from passing through. The upper surface of the water-pervious substrate at the time of application is essentially a flat surface, i. e. with the exception of small holes or other irregularities due to the nature of the material and a certain possible radius of curvature. This makes it possible to obtain a uniformly thin, as uniform as possible wet pulp web or wet paper structure or wet paper sheet. After the application of the second aqueous pulp slurry containing the polymer P, part of the water (a-a) flows through the fine holes, while sheeting occurs on the upper side, thus forming a wet paper structure. The wet paper structure thus obtained is flat, i. it has an extremely small height compared to its length and width. The pulp contained in the second pulp slurry containing polymer P, as well as possible other components to be contained in the final paper or board produced, such as filler (a-e), ideally remain completely in the wet paper structure that is formed. In this method, it is effective to use possible additional components in the second aqueous pulp slurry containing polymer P, which are added to assist in the retention of other components, to assist in dewatering, or to assist in the formation of a uniform sheet, for example, an organic polymer (a-d). In most cases, these possible additional components contained in the pulp slurry also remain completely or at least substantially remain in the resulting pulp web. The portion of the wet paper structure that determines the solids content of the wet paper structure contains retained pulp components, possible other components to be contained in the final manufactured paper, and possible additional components. Depending on the retention characteristics of these components, these may include, for example, said pulp, organic polymers, fillers, and other paper auxiliaries. After step (B) is completed, the wet paper structure is strong enough to be removed from the water-permeable substrate.

Preferably, the water-permeable substrate used in step (B) is a mesh. The mesh, which contains the bottom side of the mesh and the upper side of the mesh, is a mesh with fine holes. The mesh includes, for example, a metal or plastic mesh. In the case of a paper machine, it is more preferred if the mesh is an endless mesh. After separating the resulting wet paper structure from the endless wire, the endless wire moves back to deposit the mass, where a new second pulp slurry containing polymer P is applied to the moving endless wire. More preferred is an infinite grid moving around several cylinders. Known types of wires designed for endless wires are Fourdrinier, a two-layer forming wire including an endless bottom wire and one of its additional endless top wires, a round wire cylinder and a round wire forming wire. Fourdrinier is preferred.

The solids content of the wet paper structure obtained in step (B) is preferably 18.7 to 24 wt. %, more preferably from 18.8 to 23 wt. %, particularly preferably from 18.9 to 22 wt. %, more preferably from 19.0 to 21 wt. % and most preferably from 19.0 to 20.7 wt. %.

In step (C), the wet paper structure obtained in step (B) is dehydrated to produce paper or board. Preferably, the dewatering carried out in step (C) comprises the following steps: (C-1) dewatering the wet paper structure by pressing to obtain a wet paper sheet;

(C-2) dehydrating the wet paper sheet by applying heat to form paper or paperboard.

The pressing of the wet paper structure carried out in step (C-1) leads to additional dewatering and a corresponding increase in solids content. In the case of press dewatering, mechanical pressure is applied to the wet paper structure. Removing water by applying mechanical pressure is more energy efficient than drying by applying heat. When the wet paper structure is placed on a water-absorbing sheet or tape, such as a batt, dehydration is aided by the adsorption of the pressed water. A cylinder is suitable for exerting pressure on the paper web. Particularly suitable is the passage of the paper web through two cylinders, optionally stopping at the water-absorbing web. The surface of the cylinder is made of, for example, steel, granite or hard rubber. The surface of the cylinder may be coated with a water-absorbing material. Water-absorbing materials have high absorbency, porosity, strength and elasticity. After contact with the wet paper structure, the water-absorbing materials are in turn re-dehydrated, for example with a rubber roller to remove the moisture. After completion of step (C-1), a wet paper sheet is obtained. After the completion of step (C-1), the wet paper sheet is hard enough to be carried to the next step (C-2) without the use of a mechanical support. The wet paper sheet preferably has a solids content of 35 to 65 wt. %, more preferably from 37 to 60 wt. %, particularly preferably from 38 to 55 wt. %, most preferably from 40 to 50 wt. %.

In step (C-2), the wet paper sheet obtained in step (C-1) is further dehydrated by applying heat, resulting in paper or paperboard. The supply of heat to the wet paper sheet is provided, for example, by means of heated plates on which the wet paper sheet is placed, by means of heated cylinders over which the wet paper sheet is passed, by means of PC (infrared) sources, by means of warm air passed over wet paper sheet or using a combination of two, three or all methods.

The resulting paper or paperboard has the highest strength compared to that of a wet paper structure or a wet paper sheet. It is assumed that with a dry matter content of 80 wt. %, hydroxyl groups contained in cellulose fibers are increasingly connected by hydrogen bonds, this provides preliminary mechanical felting of the fibers. An indicator of the strength of the resulting paper or board is, for example, the internal strength.

Preferably, if the solids content in the resulting paper or board is not less than 88 wt. %. More preferably, if the solids content in the resulting paper or board is from 89 to 100 wt. %, particularly preferably from 90 to 98 wt. % and most preferably from 91 to 96 wt. %.

Depending on the basis weight per unit area, also known as the density, the name of the flat molded product obtained from the second pulp slurry containing polymer ^P changes. referred to as paper in the present invention and having a density of 225 g/m ² or more is referred to as board in the present invention. The density of the paper or paperboard is preferably 20 to 400 g/m ² , more preferably 40 to 280 g/m ² , particularly preferably 60 to 200 g/m ² , more preferably 80 to 160 g/m ² , even more preferably 90 to 140 g/m ² and most preferably 100 to 130 g/m ² .

Preferably, if the resulting paper or paperboard is packaging paper, more preferably corrugated material.

The preferences given for the method of making paper or paperboard also apply to other aspects of the present invention.

Another object of the present invention is paper or paperboard obtained by a process comprising the following steps:

(A) adding a water-soluble polymer P to a first aqueous pulp suspension having a solids content of 0.1 to 6 wt. %, thus obtaining a second aqueous pulp suspension containing polymer P obtained by

- proceeding to obtain polymer V radical polymerization (i) from 33 to 83 mol. % monomer of formula I

in which R ¹ =H or C ₁ -C ₆ -alkyl,

(ii) from 6 to 56 mol. % diallyldimethylammonium chloride, diallyldiethylammonium chloride, or a salt of a monoethylenically unsaturated monomer containing a quaternized nitrogen atom, which is the only charged group at a pH value of 7,

(iii) from 11 to 61 mol. % monoethylenically unsaturated carboxylic acid, monoethylenically unsaturated sulfonic acid or monoethylenically unsaturated phosphonic acid, or their salts,

(iv) 0 to 50 mol. % of one or more ethylenically unsaturated monomers other than the monomer (i), (ii) and (iii),

where the total amount of all monomers (i), (ii), (iii) and (iv) is 100 mol. %,

And

- hydrolysis of the NC(=O)R ¹ groups contained in the units of the monomers of formula (I), polymerized to obtain polymer V, with the formation of primary amino groups or amide groups in the polymer P, where at least 87% of the units of the monomers of formula (I) are hydrolyzed , polymerized to obtain polymer V, in terms of the amount of all units of the monomers of formula I, polymerized to obtain polymer V,

(B) dewatering a second aqueous pulp slurry containing polymer P on a permeable support to form a wet paper structure having a solids content of 18.5 to 25 wt. %,

(C) dewatering the wet paper structure to produce paper or board.

The paper or board preferably has an internal strength of 190 to 450 J/m ² , more preferably 195 to 380 J/m ² , particularly preferably 200 to 340 J/m ² and most preferably 205 to 300 J/m ² , the internal strength corresponds to that determined in accordance with the standard method of Tappi (Technical Society of the Pulp and Paper Industry) T833 pm-94.

Another object of the present invention is a water-soluble polymer P obtained by

- proceeding to obtain polymer V radical polymerization (i) from 33 to 83 mol. % monomer of formula I

in which R ¹ =H or C ₁ -C ₆ -alkyl,

(ii) from 6 to 56 mol. % diallyldimethylammonium chloride, diallyldiethylammonium chloride, or a salt of a monoethylenically unsaturated monomer containing a quaternized nitrogen atom, which is the only charged group at a pH value of 7,

(iii) from 11 to 61 mol. % monoethylenically unsaturated carboxylic acid, monoethylenically unsaturated sulfonic acid or monoethylenically unsaturated phosphonic acid, or their salts,

(iv) 0 to 50 mol. % of one or more ethylenically unsaturated monomers other than the monomer (i), (ii) and (iii),

where the total amount of all monomers (i), (ii), (iii) and (iv) is 100 mol. %,

And

- hydrolysis of the NC(=O)R ¹ groups contained in the units of the monomers of formula (I), polymerized to obtain polymer V, with the formation of primary amino groups or amide groups in the polymer P, where at least 87% of the units of the monomers of formula (I) are hydrolyzed , polymerized to obtain polymer V, in terms of the amount of all units of the monomers of formula I, polymerized to obtain polymer V.

EXAMPLES

The percentage values given in the examples are by weight.

A) Additives

A-1) Polymer characterization techniques

Solids content was determined by placing 0.5 to 1.5 g of the polymer solution in a 4 cm diameter metal cap and then drying in a convection dryer at 140° C. for 120 minutes. The ratio of the weight of the sample after drying under the above conditions to the weight of the weighed sample, multiplied by 100, gives the solids content of the polymer, expressed in wt. %. Drying was carried out at ambient pressure, possibly at 101.32 kPa, without correcting for any variation due to weather or altitude.

The degree of hydrolysis means the percentage of the amount of hydrolyzed N-CHO groups contained in the N-vinylformamide monomers used in the polymerization reaction, based on the total amount of N-vinylformamide used in the polymerization reaction. The degree of hydrolysis of homopolymers or copolymers polymerized with N-vinylformamide and subjected to hydrolysis was determined by enzymatic analysis of formic acid or formates released during hydrolysis (assay kit obtained from Boehringer, Mannheim).

Polymer content refers to the percentage by weight of polymer in solution without counterions, i.e. counterions are ignored. The polymer content means the sum, expressed in mass percent, of the amounts of all structural units of the polymer in grams, which are contained in 100 g of an aqueous solution. It was determined by calculation. In this case, possibly charged structural units in charged form, ie, for example, amino groups in protonated form and carboxy groups in deprotonated form, are included. Counterions of charged structural units, such as sodium cation, chloride ion, phosphate ion, formate ion, acetate ion, etc., were not taken into account. The calculation can be carried out in such a way that for a mixture, based on the amounts of monomers used, optionally the degree of hydrolysis of certain monomers and optionally the proportion of reagents that reacted in a polymer-similar way by reacting with the polymer to form a covalent bond, the molar amounts of the structural units of the polymer contained after completion of the reaction, and they were converted into mass fractions using the molar masses of the structural units. In this case, the full degree of conversion of all monomers or reagents was usually implied, i.e. component 100%. In this procedure, the sum of the mass fractions gave the total amount of polymer. The polymer content was the ratio of the total amount of polymer to the total weight of the mixture. Thus, in addition to the total amount of polymer indicated above, the total weight of the mixture included the weight of the reaction medium, possible cations or anions, and any substances that were added to the reaction mixture and which are not meant to be included in the polymer. The mass of substances removed from the reaction mixture (eg, water distilled off if necessary, etc.) was subtracted.

The total content of primary amino groups and/or amidine groups can be determined by the same procedure as described above for determining the content of the polymer. Taking into account the amounts of monomers used, the analytically determined degree of hydrolysis, the ratio of amidine groups to the number of primary amino groups, determined by ¹³ C-NMR spectroscopy (nuclear magnetic resonance), and, if appropriate, the proportion of reactants that reacted with the polymer polymer similarly by reaction with the polymer with the formation of a covalent bond, was determined by the molar composition of the structural units of the polymer contained after completion of the reaction. Using the molar masses of the individual structural units, it is possible to calculate, expressed in milliequivalents, the molar content of the primary amino groups and/or amidine units that are contained in 1 g of the polymer. To determine quantities using ¹³ C-NMR spectroscopy, the ratio of the area under the peak for the formate group HCOO- (173 [ppm]) to the area under the peak for the amidine group -N=CH-N- (152 ppm) can be calculated ).

K values were determined according to H. Fikentscher, Cellulose Chemistry, Volume 13, 48-64 and 71-74 under the conditions indicated for each case. The values in parentheses indicate the concentration of the solution, calculated taking into account the content of the polymer and solvent. The measurements were carried out at 25°C and at a pH value of 7.5.

Unless otherwise indicated, only completely demineralized water was used to prepare additives.

A-2) Polymerization and hydrolysis reactions

Example P-P1: additive 1

((Hydrolyzed terpolymer: VFA(N-vinylformamide)/DADMAC/Na acrylate=40 mole %/30 mole %/30 mole %, K value=95)

a) Polymerization of precursor V1

As download 1 used a mixture of 209.8 g 32 wt. % aqueous solution of Na acrylate, the pH value of which was provided equal to 6.4, and 68.3 g of N-vinylformamide.

As load 2, 1.5 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 74.5 g of water.

As load 3, 1.6 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 80.4 g of water.

200 g of water was used as load 4 and 340 g of water was used as load 5.

200 g of water and 2.2 g of 75 wt. % phosphoric acid solution. At a stirring speed of 100 rpm, was added about 3.0 g of 25 wt. % caustic soda solution, thus providing a pH value of 6.5. Then interfered with 177.3 g of 65 wt. % aqueous solution of DADMAC (diallyldimethylammonium chloride). The receiver was heated to 63°C and the pressure in the apparatus was reduced to equal to about 210 mbar, so that the reaction mixture just started to boil at 63°C. Then began the simultaneous addition of downloads 1 and 2 and they were dosed synchronously for 4 h at a constant temperature equal to 63°C. 1.5 hours after the start of adding load 1, the addition of water load 4 was started and it was dosed over 2.5 hours. After the addition of loads 1, 2 and 4 was completed, load 3 was added within 2 hours. 30 minutes after the start of adding load 3 (= 4.5 hours after the start of adding load 1) the pressure was set to 500 mbar and the internal temperature was raised to 85°C. After the addition of batch 3 was completed, the mixture was held at 85°C for another 1 hour and then batch 5 was stirred in as quickly as possible. The mixture was cooled to room temperature and the vacuum was stopped by blowing with normal air. During the entire polymerization time (7 h), water was constantly distilled off, thus, a total of 108 g was distilled off.

The result was a yellow, highly viscous solution having a solids content of 20.5 wt. %. The K value of the copolymer was 95 (0.5 wt.% in 5 wt.% aqueous NaCl solution).

b) Hydrolysis to obtain the final product - additive 1

In a 500 ml four-necked flask equipped with a stirrer in the form of a sheet, a thermometer for measuring the internal temperature, an addition funnel and a reflux condenser, 190.0 g of the polymer VI solution obtained above was mixed with 0.8 g of 40 wt. % aqueous bisulfite solution at a stirrer speed of 80 rpm and then heated to 80°C. Then 28.0 g of 25 wt. % aqueous sodium hydroxide solution. The mixture was kept at 80° C. for 7 hours. The resulting product was cooled to room temperature and the pH was adjusted to 6.8 by adding 15.9 g of 37 wt. % hydrochloric acid solution.

A yellowish viscous polymer solution was obtained having a solids content of 20.6 wt. %, and a polymer content of 12.0 wt. %. The degree of hydrolysis of vinylformamide units was 94 mol. %.

Example P-P2: additive 2

(hydrolyzed terpolymer: VFA/DADMAC/Na acrylate=35 mol%/35 mol%/30 mol%, K value=79)

a) Polymerization of precursor V2

As download 1 used a mixture of 209.8 g 32 wt. % aqueous solution of Na acrylate, the pH value of which was provided equal to 6.4, and 59.8 g of N-vinylformamide.

As load 2, 1.6 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 78.4 g of water.

As load 3, 1.7 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 84.3 g of water.

200 g of water was used as load 4 and 340 g of water was used as load 5.

200 g of water and 2.2 g of 75 wt. % phosphoric acid solution. At a stirring speed of 100 rpm, was added about 3.0 g of 25 wt. % caustic soda solution, thus providing a pH value of 6.5. Then 206.8 g of 65 wt. % aqueous solution of DADMAC. The receiver was heated to 63°C and the pressure in the apparatus was reduced to equal to about 210 mbar, so that the reaction mixture just started to boil at 63°C. Then began the simultaneous addition of downloads 1 and 2 and they were dosed synchronously for 4 h at a constant temperature equal to 63°C. 1.5 hours after the start of adding load 1, the addition of water load 4 was started and it was added within 2.5 hours. After the addition of loads 1, 2 and 4 was completed, load 3 was added within 2 hours. 30 minutes after the start of adding load 3 (= 4.5 hours after the start of adding load 1) the pressure was set to 500 mbar and the internal temperature was raised to 85°C. After the addition of batch 3 was completed, the mixture was held at 85°C for another 1 hour and then batch 5 was stirred in as quickly as possible. The mixture was cooled to room temperature and the vacuum was stopped by blowing with normal air. During the entire polymerization time (7 h), water was constantly distilled off, thus, only 96 g was distilled off.

The result was a yellow viscous solution having a solids content of 20.6 wt. %. The K value of the copolymer was 79 (0.5 wt. %) in 5 wt. % aqueous solution of NaCl).

b) Hydrolysis to obtain the final product

In a 500 ml four-necked flask equipped with a stirrer in the form of a sheet, a thermometer for measuring the internal temperature, an addition funnel and a reflux condenser, 190.0 g of the polymer V2 solution obtained above was mixed with 0.6 g of 40 wt. % aqueous sodium bisulfite solution at a stirrer speed of 80 rpm and then heated to 80°C. Then 25.0 g of 25 wt. % aqueous sodium hydroxide solution. The mixture was kept at 80° C. for 8 hours. The resulting product was cooled to room temperature and the pH was adjusted to 6.7 by adding 13.1 g of 37 wt. % hydrochloric acid solution.

A yellowish viscous polymer solution was obtained having a solids content of 20.6% and a polymer content of 12.7%. The degree of hydrolysis of vinylformamide units was 95 mol. %.

Example P-P3: additive 3

(hydrolysed terpolymer: VFA/DADMAC/Na acrylate=40 mol %/40 mol %/20 mol %, K value=71)

a) Polymerization of precursor V3

As download 1 used a mixture of 134.2 g 32 wt. % aqueous solution of Na acrylate, the pH value of which was provided equal to 6.4, and 65.5 g of N-vinylformamide.

As load 2, 1.6 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 78.4 g of water.

As load 3, 1.4 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 70.6 g of water.

200 g of water was used as load 4 and 540 g of water was used as load 5.

200 g of water and 2.2 g of 75 wt. % phosphoric acid solution. At a stirring speed of 100 rpm, was added about 3.0 g of 25 wt. % caustic soda solution, thus providing a pH value of 6.5. Then 226.8 g of 65 wt. % aqueous solution of DADMAC. The receiver was heated to 63°C and the pressure in the apparatus was reduced to equal to about 210 mbar, so that the reaction mixture just started to boil at 63°C. Then began the simultaneous addition of downloads 1 and 2 and they were dosed synchronously for 4 h at a constant temperature equal to 63°C. 1.5 hours after the start of adding load 1, the addition of water load 4 was started and it was added within 2.5 hours. After the addition of loads 1, 2 and 4 was completed, load 3 was added within 2 hours. 30 minutes after the start of adding load 3 (= 4.5 hours after the start of adding load 1) the pressure was set to 500 mbar and the internal temperature was raised to 85°C. After the addition of batch 3 was completed, the mixture was held at 85°C for another 1 hour and then batch 5 was stirred in as quickly as possible. The mixture was cooled to room temperature and the vacuum was stopped by blowing with normal air. During the entire polymerization time (7 h), water was constantly distilled off, thus, a total of 207 g was distilled off.

The result was a yellowish viscous solution having a solids content of 20.8 wt. %. The K value of the copolymer was 71 (0.5 wt.% in 5 wt.% aqueous NaCl solution).

b) Hydrolysis to obtain the final product

In a 500 ml four-necked flask equipped with a stirrer in the form of a sheet, a thermometer to measure the internal temperature, an addition funnel and a reflux condenser, 210.0 g of the polymer V3 solution obtained above was mixed with 0.8 g of 40 wt. % aqueous sodium bisulfite solution at a stirrer speed of 80 rpm and then heated to 80°C. Then 26.8 g of 25 wt. % aqueous sodium hydroxide solution. The mixture was kept at 80° C. for 5.5 hours. The resulting product was cooled to room temperature and the pH was adjusted to 7.0 by adding 13.7 g of 37 wt. % hydrochloric acid solution.

A yellowish viscous polymer solution was obtained having a solids content of 20.5 wt. %, and a polymer content of 12.7 wt. %. The degree of hydrolysis of vinylformamide units was 97 mol. %.

Example P-P4: additive 4

(hydrolyzed terpolymer: VFA/DADMAC/Na acrylate=50 mol %/20 mol %/30 mol %, K value=97)

a) Polymerization of V4 precursor

As download 1 used a mixture of 284.1 g 32 wt. % aqueous solution of Na acrylate, the pH value of which was provided equal to 6.4, and 115.6 g of N-vinylformamide (99%).

As load 2, 0.9 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 45.4 g of water.

As load 3, 1.7 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 84.2 g of water.

200 g of water was used as load 4 and 228 g of water was used as load 5.

Into a 2 L glass apparatus equipped with an anchor stirrer, a descending condenser, a thermometer for measuring the internal temperature, and a nitrogen inlet, was added 200 g of water and 3.0 g of 75 wt. % phosphoric acid solution. At a stirring speed of 100 rpm, about 4.7 g of 25 wt. % caustic soda solution was added to provide a pH value of 6.6. Then interfered with 160.0 g of 65 wt. % aqueous solution of DADMAC. The receiver was heated to 66°C and the pressure in the apparatus was reduced to equal to about 250 mbar, so that the reaction mixture just started to boil at 66°C. Then began the simultaneous addition of downloads 1 and 2 and they were dosed synchronously for 4 h at a constant temperature equal to 66°C. 1.5 hours after the start of adding load 1, the addition of water load 4 was started and it was added within 2.5 hours. After the addition of loads 1, 2 and 4 was completed, load 3 was added within 2 hours. After 1 hour after the start of adding load 3 (= 5 hours after the start of adding load 1) the pressure was set to 650 mbar and the internal temperature was raised to 90°C. After the addition of batch 3 was completed, the mixture was held at 85°C for another 1 hour and then batch 5 was stirred in as quickly as possible. The mixture was cooled to room temperature and the vacuum was stopped by blowing with normal air. During the entire polymerization time (7 h), water was constantly distilled off, thus, only 78 g was distilled off.

The result was a yellowish, highly viscous solution having a solids content of 26.7 wt. %. The K value of the copolymer was 97 (0.5 wt.% in 5 wt.% aqueous NaCl solution).

b) Hydrolysis to obtain the final product

In a 500 ml four-necked flask equipped with a stirrer in the form of a sheet, a thermometer to measure the internal temperature, an addition funnel and a reflux condenser, 180.0 g of the polymer V4 solution obtained above was mixed with 1.3 g of 40 wt. % aqueous sodium bisulfite solution at a stirrer speed of 80 rpm and then heated to 80°C. Then 43.1 g of 25 wt. % aqueous sodium hydroxide solution. The mixture was kept at 80° C. for 6 hours. The resulting product was cooled to room temperature and the pH was adjusted to 7.8 by adding 21.2 g of 37 wt. % hydrochloric acid solution.

The result was a yellowish viscous polymer solution having a solids content of 24.8 wt. %, and a polymer content of 13.8 wt. %. The degree of hydrolysis of vinylformamide units was 95 mol. %.

Example P-P5: additive 5

(hydrolyzed terpolymer: VFA/DADMAC/Na acrylate=60 mol %/10 mol %/30 mol %, K value=100)

a) Polymerization of V5 precursor

As download 1 used a mixture of 313.6 g 32 wt. % aqueous solution of Na acrylate, the pH value of which was provided equal to 6.4, and 153.2 g of N-vinylformamide.

As load 2, 1.8 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 86.7 g of water.

As load 3, 1.0 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 47.6 g of water.

200 g of water was used as load 4 and 265 g of water was used as load 5.

Into a 2 L glass apparatus equipped with an anchor stirrer, a descending condenser, a thermometer for measuring the internal temperature, and a nitrogen inlet, was added 200 g of water and 3.0 g of 75 wt. % phosphoric acid solution. At a stirring speed of 100 rpm, about 4.7 g of 25 wt. % caustic soda solution, thus providing a pH value of 6.5. Then 88.3 g of 65 wt. % aqueous solution of DADMAC. The receiver was heated to 63°C and the pressure in the apparatus was reduced to equal to about 210 mbar, so that the reaction mixture just started to boil at 63°C. Then began the simultaneous addition of downloads 1 and 2 and they were dosed synchronously for 4 h at a constant temperature equal to 63°C. 1.5 hours after the start of adding load 1, the addition of water load 4 was started and it was added within 2.5 hours. After the addition of loads 1, 2 and 4 was completed, load 3 was added within 2 hours. After 1 hour after the start of adding load 3 (= 5 hours after the start of adding load 1) the pressure was set to 380 mbar and the internal temperature was raised to 75°C. After the addition of batch 3 was completed, the mixture was held at 75°C for another 1 hour and then batch 5 was stirred in as quickly as possible. The mixture was cooled to room temperature and the vacuum was stopped by blowing with normal air. During the entire polymerization time (7 h), water was constantly distilled off, thus, only 114 g was distilled off.

The result was a yellow, highly viscous solution having a solids content of 24.5 wt. %. The K value of the copolymer was 100 (0.5 wt.% in 5 wt.% aqueous NaCl solution).

b) Hydrolysis to obtain the final product

In a 500 ml four-necked flask equipped with a stirrer in the form of a sheet, a thermometer to measure the internal temperature, an addition funnel and a reflux condenser, 170.0 g of the polymer V5 solution obtained above was stirred 1.5 g of 40 wt. % aqueous sodium bisulfite solution at a stirrer speed of 80 rpm and then heated to 80°C. Then 49.5 g of 25 wt. % aqueous sodium hydroxide solution. The mixture was kept at 80° C. for 7 hours. The resulting product was cooled to room temperature and the pH was adjusted to 8.1 by adding 22.2 g of 37 wt. % hydrochloric acid solution.

A yellowish viscous polymer solution was obtained having a solids content of 22.9 wt. %, and a polymer content of 11.8 wt. %. The degree of hydrolysis of vinylformamide units was 96 mol. %.

Example P-P6: Additive 6

(hydrolyzed VFA/DADMAC/Na/TAAX acrylate (tetraallylammonium chloride) = 39.99 mol%/30.02 mol%/29.97 mol%/0.02 mol%, simplified description: cross-linked hydrolyzed terpolymer : WFA/DADMAC/Na acrylate=40 mol %/30 mol %/30 mol % with addition of 0.02 mol % TAAX crosslinker, K value=86)

a) Polymerization of V6 precursor

As download 1 used a mixture of 209.8 g 32 wt. % aqueous solution of Na acrylate, the pH value of which was provided equal to 6.4, 68.3 g of N-vinylformamide and 0.1 N,N,N-tetraallylammonium chloride.

As load 2, 1.5 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 74.5 g of water.

As load 3, 1.6 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 80.4 g of water.

200 g of water was used as load 4 and 340 g of water was used as load 5.

200 g of water and 2.2 g of 75 wt. % phosphoric acid solution. At a stirring speed of 100 rpm, was added about 3.0 g of 25 wt. % caustic soda solution, thus providing a pH value of 6.5. Then interfered with 177.3 g of 65 wt. % aqueous solution of DADMAC. The receiver was heated to 63°C and the pressure in the apparatus was reduced to equal to about 210 mbar, so that the reaction mixture just started to boil at 63°C. Then began the simultaneous addition of downloads 1 and 2 and they were dosed synchronously for 4 h at a constant temperature equal to 63°C. 1.5 hours after the start of adding load 1, the addition of water load 4 was started and it was added within 2.5 hours. After the addition of loads 1, 2 and 4 was completed, load 3 was added within 2 hours. 30 minutes after the start of adding load 3 (= 4.5 hours after the start of adding load 1) the pressure was set to 500 mbar and the internal temperature was raised to 85°C. After the addition of batch 3 was completed, the mixture was held at 85°C for another 1 hour and then batch 5 was stirred in as quickly as possible. The mixture was cooled to room temperature and the vacuum was stopped by blowing with normal air. During the entire polymerization time (7 h), water was constantly distilled off, thus, only 109 g was distilled off.

The result was a yellow viscous solution having a solids content of 20.4 wt. %. The K value of the copolymer was 86 (0.5 wt. %) in 5 wt. % aqueous solution of NaCl).

b) Hydrolysis to obtain the final product

In a 500 ml four-necked flask equipped with a stirrer in the form of a sheet, a thermometer to measure the internal temperature, an addition funnel and a reflux condenser, 190.0 g of the polymer V6 solution obtained above was mixed with 0.8 g of 40 wt. % aqueous sodium bisulfite solution at a stirrer speed of 80 rpm and then heated to 80°C. Then 25.3 g of 25 wt. % aqueous sodium hydroxide solution. The mixture was kept at 80° C. for 7 hours. The resulting product was cooled to room temperature and the pH was adjusted to 6.8 by adding 13.8 g of 37 wt. % hydrochloric acid solution.

A yellowish viscous polymer solution was obtained having a solids content of 20.1 wt. %, and a polymer content of 12.2 wt. %. The degree of hydrolysis of vinylformamide units was 93 mol. %.

Example P-P7: additive 7

(hydrolyzed terpolymer: VFA/DADMAC/Na methacrylate=40 mol %/30 mol %/30 mol %, K value=74)

a) Polymerization of V7 precursor

As download 1 used a mixture of 257.1 g 30 wt. % aqueous solution of Na methacrylate, the pH value of which was provided equal to 6.4, and 68.3 g of N-vinylformamide.

As load 2, 1.6 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 77.4 g of water.

As load 3, 1.7 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 84.3 g of water.

As load 4 used 340 g of water.

200 g of water and 2.2 g of 75 wt. % phosphoric acid solution. At a stirring speed of 100 rpm, was added about 3.0 g of 25 wt. % caustic soda solution, thus providing a pH value of 6.5. Then interfered with 177.3 g of 65 wt. % aqueous solution of DADMAC. The receiver was heated to 63°C and the pressure in the apparatus was reduced to equal to about 210 mbar, so that the reaction mixture just started to boil at 63°C. Then began the simultaneous addition of downloads 1 and 2 and they were dosed synchronously for 4 h at a constant temperature equal to 63°C. After completion of the addition of Loads 1 and 2, Load 3 was added within 2 hours. 30 minutes after the start of the addition of Load 3 (= 4.5 hours after the start of the addition of Load 1), the pressure was set to 500 mbar and the internal temperature was raised to 85°C . After the addition of batch 3 was completed, the mixture was held at 85°C for another 1 hour and then batch 4 was stirred in as quickly as possible. The mixture was cooled to room temperature and the vacuum was stopped by blowing with normal air. During the entire polymerization time (7 h), water was constantly distilled off, thus, only 138 g was distilled off.

The result was a yellow, highly viscous solution having a solids content of 24.8 wt. %. The K value of the copolymer was 74 (0.5 wt.% in 5 wt.% aqueous NaCl solution).

b) Hydrolysis to obtain the final product

In a 500 ml four-necked flask equipped with a stirrer in the form of a sheet, a thermometer for measuring the internal temperature, an addition funnel and a reflux condenser, 180.0 g of the polymer V7 solution obtained above was mixed with 0.8 g of 40 wt. % aqueous sodium bisulfite solution at a stirrer speed of 80 rpm and then heated to 80°C. Then 30.6 g of 25 wt. % aqueous sodium hydroxide solution. The mixture was kept at 80° C. for 8 hours. The resulting product was cooled to room temperature and the pH was adjusted to 6.8 by adding 17.0 g of 37 wt. % hydrochloric acid solution.

The result was a yellowish viscous polymer solution having a solids content of 25.0 wt. %, and a polymer content of 14.4 wt. %. The degree of hydrolysis of vinylformamide units was 90 mol. %.

Example P-P8: additive 8

(hydrolyzed terpolymer: VFA/DADMAC/Na acrylate=40 mol %/30 mol %/30 mol %, K value=97)

a) Polymerization of V8 precursor

As download 1 used a mixture of 209.8 g 32 wt. % aqueous solution of Na acrylate, the pH value of which was provided equal to 6.4, and 68.3 g of N-vinylformamide.

As load 2, 1.5 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 74.5 g of water.

As load 3, 1.6 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 80.4 g of water.

200 g of water was used as load 4 and 390 g of water was used as load 5.

200 g of water and 2.2 g of 75 wt. % phosphoric acid solution. At a stirring speed of 100 rpm, was added about 3.0 g of 25 wt. % caustic soda solution, thus providing a pH value of 6.5. Then interfered with 177.3 g of 65 wt. % aqueous solution of DADMAC. The receiver was heated to 63°C and the pressure in the apparatus was reduced to equal to about 210 mbar, so that the reaction mixture just started to boil at 63°C. Then began the simultaneous addition of downloads 1 and 2 and they were dosed synchronously for 4 h at a constant temperature equal to 63°C. 1.5 hours after the start of adding load 1, the addition of water load 4 was started and it was added within 2.5 hours. After the addition of loads 1, 2 and 4 was completed, load 3 was added within 2 hours. 30 minutes after the start of adding load 3 (= 4.5 hours after the start of adding load 1) the pressure was set to 500 mbar and the internal temperature was raised to 85°C. After the addition of batch 3 was completed, the mixture was held at 85°C for another 1 hour and then batch 5 was stirred in as quickly as possible. The mixture was cooled to room temperature and the vacuum was stopped by blowing with normal air. During the entire polymerization time (7 h), water was constantly distilled off, thus only 150 g was distilled off.

The result was a yellow, highly viscous solution having a solids content of 20.5 wt. %. The K value of the copolymer was 97 (0.5 wt.% in 5 wt.% aqueous NaCl solution).

b) Hydrolysis to obtain the final product

In a 500 ml four-neck flask equipped with a stirrer in the form of a sheet, a thermometer for measuring the internal temperature, an addition funnel and a reflux condenser, 170.0 g of the polymer V8 solution obtained above was mixed with 0.7 g of 40 wt. % aqueous sodium bisulfite solution at a stirrer speed of 80 rpm and then heated to 80°C. Then 21.8 g of 25 wt. % aqueous sodium hydroxide solution. The mixture was kept at 80° C. for 8 hours. The resulting product was cooled to room temperature and the pH was adjusted to 7.0 by adding 11.9 g of 37 wt. % hydrochloric acid solution.

A yellowish viscous polymer solution was obtained having a solids content of 20.7 wt. %, and a polymer content of 12.5 wt. %. The degree of hydrolysis of vinylformamide units was 88 mol. %.

Example P-P9: Additive 9

(hydrolyzed terpolymer: VFA/DADMAC/Na acrylate=40 mol %/30 mol %/30 mol %, K value=97)

a) Polymerization of V9 precursor

As download 1 used a mixture of 209.8 g 32 wt. % aqueous solution of Na acrylate, the pH value of which was provided equal to 6.4, and 68.3 g of N-vinylformamide.

As load 2, 1.5 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 74.5 g of water.

As load 3, 1.6 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 80.4 g of water.

200 g of water was used as load 4 and 390 g of water was used as load 5.

200 g of water and 2.2 g of 75 wt. % phosphoric acid solution. At a stirring speed of 100 rpm, was added about 3.0 g of 25 wt. % caustic soda solution, thus providing a pH value of 6.5. Then interfered with 177.3 g of 65 wt. % aqueous solution of DADMAC. The receiver was heated to 63°C and the pressure in the apparatus was reduced to equal to about 210 mbar, so that the reaction mixture just started to boil at 63°C. Then began the simultaneous addition of downloads 1 and 2 and they were dosed synchronously for 4 h at a constant temperature equal to 63°C. 1.5 hours after the start of adding load 1, the addition of water load 4 was started and it was added within 2.5 hours. After the addition of loads 1, 2 and 4 was completed, load 3 was added within 2 hours. 30 minutes after the start of adding load 3 (= 4.5 hours after the start of adding load 1) the pressure was set to 500 mbar and the internal temperature was raised to 85°C. After the addition of batch 3 was completed, the mixture was held at 85°C for another 1 hour and then batch 5 was stirred in as quickly as possible. The mixture was cooled to room temperature and the vacuum was stopped by blowing with normal air. During the entire polymerization time (7 h), water was constantly distilled off, thus only 150 g was distilled off.

The result was a yellow, highly viscous solution having a solids content of 20.5 wt. %. The K value of the copolymer was 95 (0.5 wt.% in 5 wt.% aqueous NaCl solution).

b) Hydrolysis to obtain the final product

In a 500 ml four-necked flask equipped with a stirrer in the form of a sheet, a thermometer for measuring the internal temperature, an addition funnel and a reflux condenser, 190.0 g of the polymer V9 solution obtained above was mixed with 0.8 g of 40 wt. % aqueous sodium bisulfite solution at a stirrer speed of 80 rpm and then heated to 80°C. Then 20.7 g of 25 wt. % aqueous sodium hydroxide solution. The mixture was kept at 80° C. for 8 hours. The resulting product was cooled to room temperature and the pH was adjusted to 7.1 by adding 11.3 g of 37 wt. % hydrochloric acid solution.

A yellowish viscous polymer solution was obtained having a solids content of 20.3 wt. %, and a polymer content of 12.6 wt. %. The degree of hydrolysis of vinylformamide units was 85 mol. %.

Example P-P10: additive 10

(hydrolysed copolymer: VFA/Na acrylate=70 mol %/30 mol %, K value=90)

a) Polymerization of V10 precursor

As download 1 used a mixture of 100.0 g of water, 224.6 g of 32 wt. % aqueous solution of Na acrylate, the pH of which was provided equal to 6.4, and 128.0 g of N-vinylformamide.

As load 2, 0.9 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 125.8 g of water.

407 g of water and 1.9 g of 85 wt. % phosphoric acid solution. At a stirring speed of 100 rpm, about 3.7 g of 25 wt. % caustic soda solution, thus providing a pH value of 6.6. The receiver was heated to 80°C and the pressure in the apparatus was reduced to equal to about 450 mbar, so that the reaction mixture just started to boil at 80°C. Then the simultaneous addition of batches 1 and 2 was started. At a constant temperature of 80°C, batch 1 was added over 1.5 h and batch 2 over 2.5 h. for a further 2.5 hours. Approximately 143 g of water was distilled off during the entire polymerization and subsequent polymerization. The mixture was then cooled to room temperature at normal pressure.

The result was a yellow viscous solution having a solids content of 23.8 wt. %. The K value of the copolymer was 90 (0.5 wt. %) in 5 wt. % aqueous solution of NaCl).

b) Hydrolysis to obtain the final product

In a 2 L four-necked flask equipped with a stirrer in the form of a sheet, a thermometer to measure the internal temperature, an addition funnel and a reflux condenser, 847.2 g of the polymer V10 solution obtained above was mixed with 9.3 g of 40 wt. % aqueous bisulfite solution at a stirrer speed of 80 rpm and then heated to 80°C. Then 313.7 g of 25 wt. % aqueous sodium hydroxide solution. The mixture was kept at 80° C. for 7 hours. The resulting product was cooled to room temperature and the pH was adjusted to 8.5 by adding 117.0 g of 37 wt. % hydrochloric acid solution.

A yellowish viscous polymer solution was obtained having a solids content of 23.0 wt. %, and a polymer content of 9.9 wt. %. The degree of hydrolysis of vinylformamide units was 98 mol. %.

Example P-P11: additive 11

(hydrolyzed terpolymer: VFA/DADMAC/Na acrylate=30 mol %/30 mol %/40 mol %, K value=92)

a) Polymerization of V11 precursor

As download 1 used a mixture of 273.8 g 32 wt. % aqueous solution of Na acrylate, the pH value of which was provided equal to 6.4, and 50.1 g of N-vinylformamide.

As load 2, 1.6 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 65.0 g of water.

As load 3, 0.9 g of 2,2'-azobis(2-methylpropionamidine)dihydrochloride was used, which was dissolved at room temperature in 35.0 g of water.

200 g of water was used as load 4 and 350 g of water was used as load 5.

Into a 2 L glass apparatus equipped with an anchor stirrer, a descending condenser, a thermometer for measuring the internal temperature and a nitrogen inlet, was added 200 g of water and 2.2 g of 75 wt. % phosphoric acid solution. At a stirring speed of 100 rpm, was added about 3.0 g of 25 wt. % caustic soda solution, thus providing a pH value of 6.5. Then interfered with 173.5 g of 65 wt. % aqueous solution of DADMAC. The receiver was heated to 63°C and the pressure in the apparatus was reduced to equal to about 210 mbar, so that the reaction mixture just started to boil at 63°C. Then began the simultaneous addition of downloads 1 and 2 and they were dosed synchronously for 4 h at a constant temperature equal to 63°C. 1.5 hours after the start of adding load 1, the addition of water load 4 was started and it was added within 2.5 hours. After the addition of loads 1, 2 and 4 was completed, load 3 was added within 2 hours. 30 minutes after the start of adding load 3 (= 4.5 hours after the start of adding load 1) the pressure was set to 500 mbar and the internal temperature was raised to 85°C. After the addition of batch 3 was completed, the mixture was held at 85°C for another 1 hour and then batch 5 was stirred in as quickly as possible. The mixture was cooled to room temperature and the vacuum was stopped by blowing with normal air. During the entire polymerization time (7 h), water was constantly distilled off, thus only 85 g was distilled off.

The result was a yellow viscous solution having a solids content of 20.4 wt. %. The K value of the copolymer was 95 (0.5 wt. %) in 5 wt. % aqueous solution of NaCl).

b) Hydrolysis to obtain the final product

In a 500 ml four-necked flask equipped with a stirrer in the form of a sheet, a thermometer to measure the internal temperature, an addition funnel and a reflux condenser, 200.0 g of the polymer VII solution obtained above was mixed with 0.6 g of 40 wt. % aqueous sodium bisulfite solution at a stirrer speed of 80 rpm and then heated to 80°C. Then 19.7 g of 25 wt. % aqueous sodium hydroxide solution. The mixture was kept at 80° C. for 8 hours. The resulting product was cooled to room temperature and the pH was adjusted to 6.3 by adding 11.8 g of 37 wt. % hydrochloric acid solution.

The result was a yellowish viscous polymer solution having a solids content of 20.8 wt. %, and a polymer content of 12.9 wt. %. The degree of hydrolysis of vinylformamide units was 92 mol. %.

A-3) General description of the obtained polymers

Table TabA1 lists the monomers used to polymerize the non-hydrolyzed precursors and the K value obtained for the polymer. Table TabA2 shows the calculated content of polymerized functional groups contained in the hydrolyzed copolymers. The calculations are based on the experimentally determined degree of hydrolysis of N-vinylformamide. used for polymerization.

B) paper

B-1) Physical specifications

Determination of solids content

To determine the solids content (DM), the Wet Sample Weight (MB) was determined using a wet paper sample using a calibrated dial scale containing a pan on top, providing a weighing accuracy of 0.01 g. Preferably, the wet paper sample had an area equal to not less than 10 cm × 10 cm. Then, the wet paper sample was placed in a calibrated drying chamber, which can maintain the set temperature with a deviation of ±2°C, and dried at the set temperature of 105°C to constant weight. Typically, constant weight was achieved after 90 minutes. The still warm dry paper sample was then transferred to a desiccator containing a suitable drying agent such as silica gel. After cooling to room temperature, the weight of the dry paper sample (MS) was determined using the above balance. The solids content of the paper sample was determined in accordance with the formula CB=100×MS/MW and is indicated in wt. %. The value expressed as a percentage is often indicated with one decimal place. If this percentage value, rounded to the first decimal place, does not change, this indicates that a constant mass is ensured in the case of solids contents ranging from 1 to 100 wt. %. In the case of solids contents ranging from 0 to less than 1 wt. %, this is respectively indicated by a constant value, rounded to the second decimal place, expressed as a percentage. Drying was carried out at ambient pressure, possibly at 101.32 kPa, without correcting for any variation due to weather or altitude. Drying should be carried out at ambient pressure, if necessary at 101.32 kPa. No correction was made for slight changes in air pressure due to weather conditions or altitude. In the event that the wet sample did not yet have the consistency of a sheet, for example a pulp slurry or pulp, the wet sample was dried on a suitable tray having a large surface area.

Internal strength of the produced dry paper sheet

The prepared dry paper sheet was examined after it was stored in a climate room at a constant temperature of 23°C and a humidity of 50% for 12 hours. Internal strength was determined according to the standard Tappi method T833 pm-94. This procedure involves cutting 10 strips of paper 2.5 cm wide and 12.7 cm long from two sheets of A4 paper previously prepared from a dry paper web made with a testing machine. Each individual paper sample was attached with double-sided adhesive tape to a separate base plate and metal bracket. The metal corner was knocked out using a pendulum, tearing the test paper sample in a direction parallel to the paper surface. The amount of energy needed to carry out this procedure was determined. The instrument used for the study was the Internal Bond Test Station manufactured by TMI (Testing Machines Inc. Islandia, New York USA). The double-sided adhesive tape was a 3M product (width 25.4 mm, type Scotch #140). Using a measuring device was determined by the energy required to break, in terms of standardized surface area, expressed in J/m ² . The mean value of 10 individual measurements was calculated.

B-2) Obtaining raw materials for making paper

The raw material for the manufacture of paper was the pulp, which was obtained by grinding the paper web in a grinder. The pulp was obtained by dissolving in drinking water and mechanically processing the paper web in a grinder at a solids content of approximately 3.5 wt. %. The pulp typically had a freeness of about 50° Schopper-Rigler. The paper web was a 120 g/m ² "Testliner 2" untreated packaging paper from Thurpapier of Weinfelden (Switzerland).

B-3) Processing paper raw materials with additives

Raw materials for making paper were treated with additives or by processing "dense mass" with a solids content of 3.5 wt. %, or by processing the "liquid mass" with a solids content of 0.8 wt. %.

In the case of "processing thick mass" 500 g of pulp having a solids content of 3.5 wt. % was placed in a large glass beaker. Then, with stirring, the additive was added in the form of 2 wt. % solution in terms of polymer content. The pulp was treated with 1.315 g of 2 wt. % additive solution in terms of polymer content or using 2.63 g of 2 wt. % additive solution in terms of polymer content. This corresponded to a polymer treatment at a polymer content of 0.15% or 0.3%, based on the amount of dry pulp. Then 100 g of the treated pulp was transferred to another glass vessel and then diluted with drinking water to provide a solids content of 0.8 wt. %.

In the case of "treatment of the liquid mass" 114.3 g of pulp having a solids content of 3.5 wt. % was placed in a large glass beaker. Then the pulp was diluted with drinking water to ensure the dry matter content of 0.8 wt. %. Then, with stirring, the additive was added in the form of 2 wt. % solution in terms of polymer content. The pulp was treated with 0.3 g of 2 wt. % additive solution in terms of polymer content or using 0.6 g of 2 wt. % additive solution in terms of polymer content. This corresponded to a polymer treatment at a polymer content of 0.15% or 0.3%, based on the amount of dry pulp.

B-4) Paper making

The objective was to produce paper sheets having a density of 120 g/m ² , using as raw material an additive-treated pulp having a solids content of 0.8 wt. %, or pulp, not treated with an additive, which had a solids content of 0.8 wt. % (= control sample).

Paper sheets were made using a dynamic sheet forming machine manufactured by TechPap (France). The pulp slurry, in the present invention meaning treated or untreated pulp, was sprayed onto the mesh. The grid was fixed in a vertically located rapidly rotating drum. In this system, the dewatering and formation of the sheet is determined not only by the structure of the sheet, but mainly by the centrifugal forces inside the rotating drum. By changing the speed of rotation of the drum, it is also possible to change the centrifugal force acting on the resulting sheet structure. The result is a different degree of dehydration of the wet paper structure, which leads to different solids content in the wet paper structure. In the present invention, this means the solids content of the wet paper structure immediately after it has been removed from the water-permeable substrate (mesh) that is fixed in the drum of the dynamic sheet-forming machine. The wet paper structure in the present invention may also be referred to as a wet paper sheet, but this does not expressly mean a remoistened pre-dried paper sheet.

The number of revolutions of the drum was changed in 5 stages from 600 to 1100 revolutions/min, thus it was possible to control the solids content in the range from 15 to 21 wt. %. A small portion of the still wet paper structure was used to determine the solids content immediately after the removal of the wet paper structure from the dynamic sheeting machine wire. Under each of the conditions used, wet paper structures were obtained having two different solids contents ranging from 17 to 21 wt. %.

After removing the wet paper structure from the drum of the dynamic sheeter, the wet paper sheets were covered on both sides with blotting paper and pressed with a stationary press at a pressure of 6 bar for 30 seconds. Wet paper sheets were obtained, in which, after pressing, the solids content usually ranged from 41 to 43 wt. %. If the solids content is significantly less than the lower value, then the thickness of the blotting paper or the number of layers applied can be increased to ensure the value is in the above range.

The resulting wet paper sheet was then re-covered on both sides with clean blotting paper and then fixed in a drying cylinder and held for 10 minutes. The surface temperature of the drying cylinder was about 100°C. After drying, the obtained dry paper sheets were placed in an air-conditioned chamber for conditioning.

B-5) Manufactured paper

As control samples, three wet paper structure samples or three wet paper sheets having solids contents of 15.3 wt. %, 17.6 wt. % and 20.2 wt. % respectively. Then, the wet paper structure or wet paper sheets were pressed, and then the resulting wet paper sheets were dried.

As samples of comparative examples, samples of wet paper structure or wet paper sheets were prepared with the addition of one of additives 1-8 used at two contents (polymer content was 1.5 g and 3 g, based on 1 kg of dry pulp), and one dose to ensure the appropriate content was added to the thick mass and one dose was added to the liquid mass. The solids content of the obtained wet paper structure or wet paper sheets was less than 18.5 wt. %. Then, the wet paper structure or wet paper sheets were pressed, and then the resulting wet paper sheets were dried.

As samples of Comparative Examples IIa, wet paper structure samples or wet paper sheets were obtained with the addition of one of the additives 9-11, each of which was used at two contents (polymer content was 1.5 g and 3 g, based on 1 kg of dry pulp) , and one dose to ensure the appropriate content was added to the thick mass and one dose was added to the liquid mass. The solids content of the obtained wet paper structure or wet paper sheets was less than 18.5 wt. %. Then, the wet paper structure or wet paper sheets were pressed, and then the resulting wet paper sheets were dried.

As samples of comparative examples IIb, wet paper structure samples or wet paper sheets were prepared with the addition of one of the additives 9-11, each of which was used at two contents (polymer content was 1.5 g and 3 g, based on 1 kg of dry pulp) , and one dose to ensure the appropriate content was added to the thick mass and one dose was added to the liquid mass. The solids content in the resulting wet paper structure or wet paper sheets was more than 18.5 wt. %. Then, the wet paper structure or wet paper sheets were pressed, and then the resulting wet paper sheets were dried.

As examples of the examples of the present invention, wet paper structure samples or wet paper sheets were prepared with the addition of one of additives 1 to 8, each of which was used at two contents (polymer content was 1.5 g and 3 g in terms of 1 kg of dry pulp), and one dose of each additive to ensure the appropriate content was added to the thick mass and one dose was added to the liquid mass. The solids content in the resulting wet paper structure or wet paper sheets was more than 18.5 wt. %. Then, the wet paper structure or wet paper sheets were pressed, and then the resulting wet paper sheets were dried.

B-6) Internal strength of the produced dry paper sheets

Tables TabB1 and TabB2 show values for the internal strength of paper made by adding additives to slurry, and Tables TabB3 and TabB4 show values for the case where additives were added to stock.

The results obtained for the produced dry paper sheets, shown in tables TabB1-TabB4, show that

(i _B ) solids content in the wet paper structure or wet paper sheet, ranging from 15.3 to 20.2 wt. %, does not affect the internal strength of dry paper sheets made in control examples without the use of additives 1-11,

(ii _B ) the solids content in the wet paper structure or in the wet paper sheet, ranging from 15.3 to 19.9 wt. %, does not affect the internal strength of dry paper sheets made in comparative examples IIa and IIb using additives 9-11,

(iii _B ) the dry matter content in the wet paper structure or wet paper sheet, amounting to more than 18.5 wt. %, leads to a significant increase in the internal strength of dry paper sheets made in the examples proposed in the present invention using additives 1-8, this increase is compared with the internal strengths of dry paper sheets made in comparative examples I using additives 1-8, their difference lies in the dry matter content in the wet paper structure or wet paper sheet, which is less than 18.5 wt. %,

(iv _B ) adding additives 1-8 to the pulp having a solids content of 3.5 wt. %, and subsequent dilution to a component of 0.8 wt. %, leads to a higher internal strength than in the case of adding the same additives to the pulp, having a solids content of 0.8 wt. %, especially if 3.0 g of additive is added instead of 1.5 g of additive.

The results obtained for additives 1-11, shown in tables TabA1 and TabA2, show that:

(i _A ) the content of polymerized DADMAC, which is 10 mol. %, is the difference between the additive 5 proposed in the present invention and the comparative additive 10, in the case of which a larger amount of N-vinylformamide was used instead of DADMAC to polymerize its precursor V10,

(ii _A ) the content of polymerized N-vinylformamide, amounting to 35 mol. %, is the difference between the precursor V2 of the additive 2 proposed in the present invention, from the additive 11, in the case of which, to obtain its precursor, V11 was polymerized by 5 mol. % less than N-vinylformamide and instead polymerized by 5 mol. % more DADMAH,

(iii _A ) the degree of hydrolysis of all N-vinylformamide monomers polymerized to form V8 precursor, which is 88%, is the difference between Additive 8 of the present invention from Additive 9, which has a degree of hydrolysis of all N-vinylformamide monomers polymerized to form it predecessor V9, comprising 85%.

Claims (33)

1. Method for the manufacture of paper or cardboard, including the following steps: (A) adding a water-soluble polymer P to a first aqueous pulp suspension having a solids content of 0.1 to 6 wt. %, thus obtaining a second aqueous pulp suspension containing polymer P, where polymer P is obtained by - proceeding with obtaining polymer V radical polymerization (i) from 33 to 83 mol. % monomer of formula I

in which R ¹ =H or C ₁ -C ₆ -alkyl, (ii) from 6 to 56 mol. % diallyldimethylammonium chloride, diallyldiethylammonium chloride, or a salt of a monoethylenically unsaturated monomer containing a quaternized nitrogen atom, which is the only charged group at a pH value of 7, (iii) from 11 to 61 mol. % monoethylenically unsaturated carboxylic acid, monoethylenically unsaturated sulfonic acid or monoethylenically unsaturated phosphonic acid, or their salts, (iv) 0 to 50 mol. % of one or more ethylenically unsaturated monomers other than the monomer (i), (ii) and (iii), where the total amount of all monomers (i), (ii), (iii) and (iv) is 100 mol. %, And - hydrolysis of the NC(=O)R ¹ groups contained in the units of the monomers of formula (I), polymerized to obtain polymer V, with the formation of primary amino groups or amide groups in the polymer P, where at least 87% of the units of the monomers of formula (I) are hydrolyzed , polymerized to obtain polymer V, in terms of the amount of all units of the monomers of formula I, polymerized to obtain polymer V, (B) dewatering a second aqueous pulp slurry containing polymer P on a permeable support to form a wet paper structure having a solids content of 18.5 to 25 wt. %, (C) dewatering the wet paper structure to produce paper or board. 2. The method according to p. 1, in which the amount of monomer (i) is from 33 to 65 mol. %; the amount of monomer (ii) is from 6 to 45 mol. %; the amount of monomer (iii) is from 11 to 40 mol. %; and/or the amount of monomer (iv) is from 0 to 30 mol. %. 3. The method according to any one of paragraphs. 1 or 2, wherein monomer (ii) is diallyldimethylammonium chloride, diallyldiethylammonium chloride, N-alkyl-N'-vinylimidazolium salt, N-alkylated vinylpyridinium salt, acrylamidoalkyltrialkylammonium salt or methacrylamidoalkyltrialkylammonium salt. 4. The method according to claim 3, wherein the monomer (ii) is diallyldimethylammonium chloride. 5. The method according to any one of paragraphs. 1-4, in which the monomer (iii) is monoethylenically unsaturated C ₃ -C ₈ -mono - or dicarboxylic acid, acrylamide-2-methylpropanesulfonic acid or their salts. 6. The method according to claim 5, wherein the monomer (iii) is acrylic acid, methacrylic acid, acrylamide-2-methylpropanesulfonic acid, or salts thereof. 7. The method according to any one of paragraphs. 1-6, in which the monomer (iv) is acrylonitrile, vinyl acetate, N-vinylpyrrolidone or N-vinylimidazole. 8. The method according to any one of paragraphs. 1-7, in which in stage (A) the polymer R is added to the first pulp suspension, in which the solids content is from more than 1.5 wt. % and up to 6.0 wt. %, and the second pulp suspension containing polymer P is diluted to provide a solids content of from 0.1 to 1.5 wt. %. 9. The method according to any one of paragraphs. 1-8, wherein in step (A) a filler is added to the first pulp slurry or to the second pulp slurry containing polymer P. 10. Water-soluble polymer P obtained by - proceeding with obtaining polymer V radical polymerization (i) from 33 to 83 mol. % monomer of formula I

in which R ¹ =H or C ₁ -C ₆ -alkyl, (ii) from 6 to 56 mol. % diallyldimethylammonium chloride, diallyldiethylammonium chloride, or a salt of a monoethylenically unsaturated monomer containing a quaternized nitrogen atom, which is the only charged group at a pH value of 7, (iii) from 11 to 61 mol. % monoethylenically unsaturated carboxylic acid, monoethylenically unsaturated sulfonic acid or monoethylenically unsaturated phosphonic acid, or their salts, (iv) 0 to 50 mol. % of one or more ethylenically unsaturated monomers other than the monomer (i), (ii) and (iii), where the total amount of all monomers (i), (ii), (iii) and (iv) is 100 mol. %, And - hydrolysis of the NC(=O)R ¹ groups contained in the units of the monomers of formula (I), polymerized to obtain polymer V, with the formation of primary amino groups or amide groups in the polymer P, where at least 87% of the units of the monomers of formula (I) are hydrolyzed , polymerized to obtain polymer V, in terms of the amount of all units of the monomers of formula I, polymerized to obtain polymer V.