KR20030042447A - A process for the production of paper - Google Patents

Abstract

The present invention relates to a method for making paper from a suspension containing cellulose fibers and fillers, comprising separately adding an anionic polymer having an aromatic group and a cationic polymer having an aromatic group to the suspension, and forming and dehydrating the suspension on a wire. Is selected from condensation polymers, polysaccharides, natural aromatic polymers and modified substances thereof, and when the anionic polymer is selected from the condensation polymer, it relates to a papermaking process characterized in that it is not an anionic melamine-sulfonic acid condensation polymer. The invention also relates to a process for making paper from suspensions containing cellulose fibers and fillers comprising the steps of separately adding an anionic polymer having aromatic groups and a cationic polymer having aromatic groups to the suspension and forming and dehydrating the suspension on a wire. The polymer relates to a papermaking process characterized in that it is not anionic polystyrene sulfonate or anionic melamine-sulfonic acid condensation polymer.

Description

Papermaking Method {A PROCESS FOR THE PRODUCTION OF PAPER}

In the papermaking field, an aqueous suspension (stock solution) containing cellulose fibers, fillers and various additives is introduced into a headbox which releases the suspension on the forming wire and the web is dehydrated and dried in the drying zone of the paper machine. The white water obtained containing fine fibers, fillers and additives is usually recycled to the papermaking process. Dehydration and retention aids are usually added to the stock solution to promote dehydration and increase the adsorption of fine particles on the cellulose fibers to retain in the oil. Various dehydration and retention aids are known in the art, such as anionic, non-ionic, cationic or amphoteric organic polymers, anionic and cationic inorganics.

WO 99/55964 and WO 99/55965 disclose the use of dehydration and retention aids, including anionic and cationic polymers having aromatic groups. Cationic organic polymers are used alone or in combination with various anionic materials such as anionic organic and inorganic condensation polymers, such as sulfonated melamine-formaldehyde and silica based particles.

It would be beneficial to provide a papermaking process with improved dehydration and retention performance. It would also be beneficial to provide dehydration and retention aids including anionic and cationic polymers with improved dehydration and retention performance.

The present invention relates to a papermaking method in which anionic and cationic polymers having aromatic groups are added to a papermaking stock solution. This process improves dewatering and retention performance.

According to the present invention it has been found that the dehydration and retention performance is improved by using dehydration and retention aids, including anionic polymers having aromatic groups and cationic polymers having aromatic groups. In particular, the present invention relates to a papermaking process from a suspension containing cellulose fibers and fillers comprising the steps of separately adding an anionic polymer having an aromatic group and a cationic polymer having an aromatic group to the suspension, and forming and dehydrating the suspension on a wire. The polymeric polymer is selected from condensation polymers, polysaccharides, natural aromatic polymers and their modifications and is not anionic melamine-sulfonic acid condensation polymer if the anionic polymer is selected from the condensation polymer. The invention also relates to a papermaking process from a suspension containing cellulose fibers and fillers comprising the steps of separately adding an anionic polymer having an aromatic group and a cationic polymer having an aromatic group to the suspension and molding and dehydrating the suspension on a wire. The polymeric polymer is not anionic polystyrene sulfonate or anionic melamine-sulfonic acid condensation polymer.

Dehydration and retention aids refer to two or more components that, when added to an aqueous cellulose suspension, provide better dewatering and retention performance than those not added.

The present invention has a high degree of white water closure, when white paper is excessively recycled and limited in the introduction of new water or when making paper from stocks of all kinds of stocks, especially high content salts (high conductivity) and colloidal materials. It results in improved dewatering and retention performance in the papermaking process. The present invention provides improved papermaking processes and economical benefits by increasing the paper machine speed and reducing the additive dosage to give a corresponding retention and dehydration effect. The present invention also provides a paper having improved dry strength.

Cationic organic polymers having aromatic groups of the present invention are derived from natural or synthetic sources and can be in straight, branched and crosslinked forms. Cationic polymers are water soluble or water-dispersible. Suitable cationic polymers are cationic polysaccharides such as starch, guar gum, cellulose, chitin, chitosan, glycan, galactan, glucan, xan gum, pectin, mannan, dextrin, with starch and guar gum being preferred and , Starch is potato, corn, wheat, tapioca, rice, waxy corn, barley and cationic vinyl addition polymers (cationic chain-growth polymers), cationic polyurethanes such as acrylate, acrylamide and vinylamide based polymers Cationic synthetic organic polymers such as cationic condensation polymers. Cationic starch, cationic acrylamide based polymers having aromatic groups are particularly preferred cationic polymers.

Cationic organic polymers of the present invention may have one or more aromatic groups and the aromatic groups are the same or different. The aromatic groups of the cationic organic polymer may be present in the polymer backbone or substituents attached to the backbone. Examples of suitable aromatic groups include aryl, alkaryl and aralkyl groups such as phenyl, phenylene, naphthyl, xylene, benzyl and phenylethyl, in particular benzyl; Cationic groups, including nitrogen-containing aromatic (aryl) groups such as pyridinium and quinolinium, and derivatives thereof, which may be present in cationic polymers and monomers used in their preparation, include quaternary ammonium, tertiary amino and acid addition salts thereof. Include.

In one aspect the cationic organic polymer having an aromatic group is a polysaccharide of formula (I).

Wherein P is a residue of the polysaccharide, A ₁ is a group that attaches N to the polysaccharide residue, and is an atomic chain containing O or N atoms with C and H atoms, optionally one or more hetero, such as O or N Alkylene groups containing 2-18, in particular 2-8 carbons, substituted by atoms are common, for example alkyleneoxy groups or hydroxy propylene groups (-CH ₂ -CH (OH) -CH _2- ), R ₁ And R ₂ is H, a hydrocarbon group, in particular one or two carbon atoms, in particular an alkyl group, Q is a substituent containing an aromatic group such as benzyl and phenylethyl groups, 1-3, in particular one or two Benzyl (-CH ₂ -C ₆ H ₅ ) is preferred, with n being 2-300,000, in particular 5-200,000, even 6-125,000, or R ₁ , R ₂ and Q together with N form an aromatic group containing 5-12 carbon atoms, and X ⁻ is negative Ionic counterions, especially halides such as chlorides. Cationic polysaccharides of the present invention may contain anionic groups in small amounts. Anionic groups can be introduced by chemical treatment or present in natural polysaccharides.

In one aspect the cationic organic polymer having an aromatic group is a chain-grown polymer. Chain-grown polymers are polymers obtained by chain growth polymerization and are referred to as chain reaction polymers and chain reaction polymerization. Examples of chain-grown polymers include vinyl addition polymers obtained by polymerizing monomers having vinyl groups or ethylenically unsaturated bonds, such as polymers obtained by polymerizing cationic monomers of formula (2).

Wherein R ₃ is H or CH ₃ , R ₁ and R ₂ are alkyl groups having 1-3, in particular 1-2 carbon atoms, A ₂ is O or NH, B ₂ is 2-8, in particular 2 An alkylene or hydroxy propylene group having 4 carbon atoms, Q is an aromatic group containing substituent, in particular a benzyl and phenylethyl group, attached to the nitrogen atom by an alkylene group having 1-3, especially 1 or 2 carbon atoms Benzyl (-CH ₂ -C ₆ H ₅ ) is preferred, and X ^- is an anionic counter ion, in particular a halide such as chloride.

The monomers of formula (2) are dialkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate and dimethylaminohydroxypropyl (meth) acrylate and dimethylaminoethyl ( Dialkylaminoalkyl (meth) acrylamides such as meta) acrylamide, diethylaminoethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, diethylaminoethyl (meth) acrylamide are treated with benzyl chloride. Quaternary monomers obtained. Preferred cationic monomers of formula (2) are dimethylaminoethyl acrylate benzyl chloride quaternary salt and dimethylaminoethyl methacrylate benzyl chloride quaternary salt. Monomers of formula (2) can be copolymerized with non-ino, cationic or anionic monomers. Examples of suitable copolymerizable monomers include (meth) acrylamide; Acrylamide based monomers such as N-alkyl (meth) acrylamide and N, N-dialkyl (meth) acrylamide, acrylate based monomers such as dialkylaminoalkyl (meth) acrylates, vinyl amides. Suitable copolymerizable cationic monomers include acid addition salts of dimethylaminoethyl (meth) acrylates with quaternary salts and diallylmethylammonium chloride. Suitable copolymerizable anionic monomers include various sulfonated vinyl monomers such as acrylic acid, methacrylic acid and styrene sulfonate. Preferred copolymerizable monomers include monomers such as acrylamide and methacrylamide and cationic or amphoteric organic polymers are especially acrylamide based polymers.

Cationic vinyl addition polymers are cationic monomers having 1-99, in particular 2-50, even more 5-20 mole percent aromatic groups, and 99-1, especially 98-50, even 95-80 mole percent acrylamide or meta. It is prepared from a monomer mixture comprising copolymerizable monomers including krillamide. The monomer mixture comprises 98-50, in particular 95-80 mole% (meth) acrylamide and the sum is 100%.

Suitable cationic polycondensation polymers include cationic polyurethanes prepared from monomer mixtures comprising aromatic isocyanates or aromatic alcohols. Suitable aromatic isocyanates include diisocyanates such as toluene-2,4- and 2,6-diisocyanate and diphenyl-methane-4,4'-diisocyanate. Suitable aromatic alcohols include diols such as bisphenol A, phenyl diethanol amines, glycerol monoterephthalate and trimethylolpropane monoterephthalate. Monovalent aromatic alcohols such as phenol and derivatives thereof can be used. The monomer mixture may also include alcohols or non-aromatic isocyanates such as diisocyanates and diols known in polyurethane production. Suitable monomers containing cationic groups include 1,2-propane diol-3-dimethylamine, N-methyl diethanolamine, N-ethyl diethanolamine, N-propyl diethanolamine, Nn-butyl diethanolamine and Nt-butyl Cationic diols, such as acid addition salts and quaternization products of n_alkanediol dialkylamines and N-alkyl dialkanolamines such as diethanolamine, N-stearyl diethanolamine and N-methyl dipropanolamine. The quaternization product can be derived from alkylating agents such as methyl chloride, dimethyl sulfate, benzyl chloride and epichlorohydrin.

The weight average molecular weight of the cationic polymer varies with the polymer used and is at least 5,000, in particular at least 10,000. More often the molecular weight can be at least 150,000, in particular at least 500,000, even at least 700,000, even at least 1,000,000, at least 2,000,000. The upper limit is not critical and is about 20,000,000, in particular 15,000,000, even 10,000,000.

Cationic organic polymers can have a wide range of degrees of substitution and cationic degrees of substitution (DS _C ) are 0.005-1.0, in particular 0.01-0.5, even 0.02-0.3, even 0.025-0.2 and aromatic degrees of substitution (DS _Q ) 0.001-0.5, in particular 0.01-0.5, even 0.02-0.3, even 0.025-0.2 with anionic degree of substitution (DS _A ) of 0-0.2, especially 0-0.1, even 0-0.05 and cationic polymers have a positive total charge Has The positive charge density of the cationic polymer is 0.1-6.0 per gram of dry polymer, in particular 0.2-5.0, even 0.5-4.0 meqv.

Cationic organic polymers of the present invention having aromatic groups include those disclosed in WO99 / 55964, WO99 / 55965, WO99 / 67310.

Anionic polymers having aromatic groups are selected from condensation polymers, polysaccharides, modified polymers and natural aromatic polymers. Condensation polymers are polymers obtained by condensation polymerization. Anionic polymers in particular are condensation polymers, polysaccharides, natural aromatic polymers, and even more condensation polymers. The anionic polymers of the present invention may be linear, branched or crosslinked. In particular anionic polymers are water soluble or water dispersible. Organic polymers are preferred.

Anionic polymers of the present invention contain the same or different aromatic groups. The aromatic group of the anionic polymer may be present in the polymer backbone or substituents attached to the backbone. Examples of suitable aromatic groups include aryl, alkaryl and aralkyl groups such as phenyl, phenylene, naphthyl, xylene, benzyl and phenylethyl and derivatives thereof. Anionic groups that may be present in the anionic polymers and monomers used to make them include anionic charges and acid groups that have anionic charges when dissolved or dispersed in water, such as phosphate, phosphonate, sulfate, sulfonic acid, sulfo Nate, carboxylic acid, carboxylate, alkoxide and phenol groups, ie hydroxy substituted phenyl and naphthyl. Groups with negative charge are salts of alkali metals, alkaline earth metals or ammonia.

Suitable anionic condensation products include condensation polymers, for example condensates of aldehydes such as formaldehyde with aromatic compounds having one or more anionic groups and other co-monomers useful for condensation polymerization such as urea, especially condensed naphthalene sulfonate polymers. . Examples of aromatic compounds having anionic groups include phenol and naphthol compounds such as phenol, naphthol, resorcinol and derivatives thereof, aromatic acids and salts such as phenyl, phenol, naphthyl and naphthol acid and salts, such as benzene sulfonic acid and sulfonate, Sulfonic acids and sulfonates such as xylene sulfonic acid and sulfonate, naphthalene sulfonic acid and sulfonate, phenol sulfonic acid and sulfonate.

Further suitable anionic polycondensation products include anionic polyurethanes prepared from polymers obtained by condensation addition polymerization, such as monomer mixtures comprising aromatic isocyanates or aromatic alcohols. Suitable aromatic isocyanates include diisocyanates such as toluene-2,4- and 2,6-diisocyanate and diphenyl-methane-4,4'-diisocyanate. Suitable aromatic alcohols include diols such as bisphenol A, phenyl diethanol amines, glycerol monoterephthalate and trimethylolpropane monoterephthalate. Monovalent aromatic alcohols such as phenol and derivatives thereof can be used. The monomer mixture may also include alcohols or non-aromatic isocyanates such as diisocyanates and diols known in polyurethane production. Suitable monomers containing anionic groups are monoester reaction products of triols such as trimethylolethane, trimethylolpropane and glycerol with dicarboxylic acids and anhydrides such as succinic and anhydrides, terephthalic acid and anhydrides, such as glycerol monosuccinate, glycerol monotere Phthalate, trimethylolpropane monosuccinate, trimethylolpropane monoterephthalate, N, N-bis- (hydroxyethyl) -glycine, di- (hydroxymethyl) propionic acid, N, N-bis- (hydroxyethyl) 2-aminoethanesulfonic acid, which reacts with alkali and alkaline earth metal hydroxides such as sodium hydroxide, amines such as triethylamine, and bases such as ammonia to form alkali and alkaline earth metals or ammonium counterions.

Suitable anionic polycondensation products are usually copolymerized with acrylate- and acrylamide based monomers and anionic vinyl additions obtained from a mixture of vinyl or ethylenically unsaturated monomers comprising at least one monomer having an aromatic group and at least one monomer having an anionic group. Polymerized polymers. Suitable anionic monomers include (meth) acrylic acid and paravinyl phenol (hydroxy styrene).

Suitable anionic polysaccharides are cationic polysaccharides such as starch, guar gum, cellulose, chitin, chitosan, glycan, galactan, glucan, xan gum, pectin, mannan, dextrin, and starch and guar gum Preferred, starch is potato, corn, wheat, tapioca, rice, waxed corn, barley. In polysaccharides anionic groups are either present or introduced by chemical means. Aromatic groups of polysaccharides are introduced by known chemical methods.

The natural aromatic anionic polymers and modified products thereof of the present invention are derived from kraft lignin such as modified lignin polymers copolymerized with formaldehyde and sulfonated lignin, such as tannin extracts such as lignin sulfonate and natural polyphenol compounds present in wood extracts. Include.

The weight average molecular weight of the anionic polymer is at least 500, in particular at least 2000, even more than 5000. The upper limit is not critical and is about 20,000,000, in particular 15,000,000, even 1,000,000.

Anionic polymers can have a wide range of degrees of substitution and anionic degrees of substitution (DS _A ) are 0.01-2.0, in particular 0.02-1.8, even 0.025-1.5. The aromatic substitution degree (DS _H ) is 0.001-1.0, in particular 0.01-0.8, even 0.02-0.7 and when the anionic polymer contains a cationic group, the cationic degree of substitution (DS _C ) is 0-0.2, in particular 0-0.1, Furthermore, it is 0-0.05 and the anionic polymer has a negative total charge. The negative charge density of the anionic polymer is 0.1-6.0 per gram of dry polymer, in particular 0.5-5.0, even more 1.0-4.0 meqv.

Anionic organic polymers of the invention having aromatic groups are described in US Pat. No. 4,070,236, 5,755,930; And those disclosed in WO95 / 21295, WO95 / 21296, WO99 / 67310 and WO00 / 49227.

Examples of cationic and anionic polymer combinations of the invention

(i) cationic polysaccharides, in particular cationic starch and anionic anionic condensation polymers, in particular benzene-based and naphthalene based condensation polymers and anionic polyurethanes, in particular anionic naphthalene based condensation polymers;

(ii) cationic polysaccharides, in particular cationic starch and natural aromatic anionic polymers and their modifications, in particular anionic lignin based polymers, in particular lignin sulfonates;

(iii) cationic condensation polymers, in particular cationic vinyl addition polymers, in particular cationic acrylamide based polymers and anionic condensation polymers, in particular benzene-based and naphthalene based condensation polymers and anionic polyurethanes, in particular anionic naphthalene based condensation Polymers;

(iv) cationic chain growth polymers, in particular cationic vinyl addition polymers, in particular cationic acrylamide based polymers and natural aromatic anionic polymers and their modified products, in particular anionic lignin based polymers, in particular lignin sulfonates.

The cationic and anionic polymers of the present invention are added separately to the stock solution containing cellulose fibers rather than to the mixture containing the polymer. In particular the cationic and anionic polymers of the invention are added to the stock solutions at different points. The order of polymer addition is arbitrary. Usually the cationic polymer is added first and the anionic polymer is added later, but the order can be reversed. The polymer may be added to the stock solution to be dehydrated in various amounts depending on the stock solution type, salt content, salt type, filler content, and timing of addition. Generally, polymers are added in amounts that give a better sizing effect if they are not added, and cationic polymers are added in an amount of at least 0.001%, in particular at least 0.005% by weight, with an upper limit of 3%, especially 2.0% by weight, based on the dry stock material. to be. The anionic polymer is added in an amount of at least 0.001%, in particular at least 0.005% by weight relative to the dry stock material, with an upper limit of 3%, in particular 1.5% by weight.

Polymers having aromatic groups of the present invention can be used in combination with additional additives that are advantageous for dehydration and retention performance. Suitable additional additives include silica based particles and other compounds that increase the sizing efficiency, such as anionic microparticles such as smectite clay, low molecular weight cationic organic polymers, aluminum compounds, anionic vinyl addition polymers and the like. These compounds are disclosed in WO99 / 55964 and WO99 / 55965.

Low molecular weight (LMW) cationic organic polymers include a material called anion trap catcher (ATC). LMW cationic organic polymers are natural or synthetic and synthetic LMW polymers are preferred. Such organic polymers include LMW high charge cationic organic polymers such as homopolymers and copolymers based on polyamines, polyamidoamines, polyethyleneamines, diallyldimethyl ammonium chloride, (meth) acrylamides and (meth) acrylates. LMW cationic organic polymers are low in molecular weight of cationic organic polymers and are at least 2,000, in particular at least 10,000. The upper molecular weight limit is 700,000, in particular 500,000, even 200,000.

The aluminum compounds used in the present invention include alum, aluminate, aluminum chloride, aluminum nitrate and polyaluminum compounds (polyaluminum chloride, aluminum polysulfate, polyaluminum compounds containing chlorine and sulfate ions, polyaluminum silicate-sulfate and mixtures thereof). It includes an aluminum compound such as. The polyaluminum compound may contain anions other than chlorine, such as those generated from organic acids such as sulfuric acid, phosphoric acid, citric acid and oxalic acid.

The process of the present invention is used to make paper from high conductivity stock solutions containing cellulose fibers and fillers. The conductivity of the stock solution is at least 2.0 mS / cm, in particular at least 3.5 mS / cm, even more at least 5.0 mS / cm. Is observed. Conductivity can be measured with standard equipment such as the WTW LF 539 instrument supplied by Christiian Berner. The above mentioned values can be determined by measuring the conductivity of the cellulose suspension present or supplied in the head box of the paper machine or by measuring the conductivity of the white water obtained by suspension dehydration. High conductivity refers to a high content of salts (electrolytes), which can be derived from the various additives introduced into the stock solution, the materials used to form the stock solution, and the fresh water introduced into the process. Higher in the process of accumulating more salt in the water circulating in the process.

The present invention is a papermaking machine in which fresh water of 0-30 tons, usually less than 20 tons, in particular less than 15 tons, even less than 10 tons and even less than 5 tons is used per tonne of paper produced, which is excessively recycled to a high degree of closure. It is useful in the process. Recycling the white water obtained in the process includes mixing the white water with the cellulose fibers and the filler to form a suspension to be sized and mixing the white water with the cellulose fibers and the filler before the suspension is introduced into the forming wire for sizing. do.

In papermaking processes such as dry strength enhancers and wet strength enhancers, traditional additional additives may be used in combination with the additives according to the invention. Cellulose suspensions include kaolin, china clay, titanium dioxide, gypsum, talc, natural and synthetic calcium carbonates (eg chalk, marble powder and precipitated calcium carbonate).

The process of the present invention can be used in all kinds of papermaking processes. Paper includes not only paper but also cellulose based products in the form of sheets and webs such as boards and cardboard. The process can be used to produce paper from different types of cellulosic fiber suspensions, the suspension containing at least 25%, in particular at least 50% by weight, of cellulose fibers relative to the dry matter. Suspensions include fibers from chemical pulp such as sulphate, sulfite and organosolve pulp, chemical pulp such as chemical-thermodynamic pulp, thermomechanical pulp, refined pulp and groundwood pulp, and recycled fibers from ink removed pulp. Can be based on.

Example 1

Cationic polymers used in the test are commercially available or prepared by known procedures. Cationic polysaccharides used in the test are prepared by reacting native potato starch with quaternization reagents according to EP-A 0 189 935 and WO 99/55964. Cationic polymers C1-C3 and comparative cationic polymers C1-based-C3-based of the present invention are as follows:

C1: Cationic starch obtained by quaternizing natural potato starch to 0.5% N with 3-chloro-2-hydroxypropyl dimethyl benzyl ammonium chloride.

C2: Cationic starch obtained by quaternizing natural potato starch to 0.7% N with 3-chloro-2-hydroxypropyl dimethyl benzyl ammonium chloride.

C3: Cationic vinyl addition polymerization polymer prepared by polymerizing acrylamide (90 mol%) and acryloxyethyldimethylbenzyl ammonium chloride (10 mol%) (molecular weight 6,000,000).

C1-based: Cationic starch obtained by quaternizing natural potato starch to 0.8% N with 2,3-epoxypropyl trimethyl ammonium chloride.

C2-based: Cationic starch obtained by quaternizing natural potato starch to 0.5% N with 2,3-epoxypropyl trimethyl ammonium chloride.

C3-based: Cationic vinyl addition polymerization polymer prepared by polymerizing acrylamide (90 mol%) and acryloxyethyltrimethyl ammonium chloride (10 mol%) (molecular weight 6,000,000).

Anionic polymers used in the test are commercially available or prepared by known procedures. Among the anionic polymers used in the tests, the anionic polymers A1-A8 of the present invention and the comparative anionic polymers A1-based-A2-based are as follows:

A1: anionic polycondensate (molecular weight 20,000) of formaldehyde and naphthalene sulfonate.

A2: anionic polycondensate (molecular weight 110,000) of formaldehyde and naphthalene sulfonate.

A3: Anionic polycondensate (molecular weight 40,000) of formaldehyde and naphthalene sulfonate.

A4: anionic polycondensate (molecular weight 210,000) of formaldehyde and naphthalene sulfonate.

A5: Anionic polyurethane obtained by reacting glycerol monostearate with toluene diisocyanate for pre-polymer formation containing terminal isocyanate groups which are subsequently reacted with dimethylol propionic acid.

A6: Anionic polyurethane obtained by reacting phenyl diethanol amine with toluene diisocyanate for pre-polymer formation containing terminal isocyanate groups which are subsequently reacted with dimethylol propionic acid and N-methyl dietanolol amine.

A7: anionic sulfonated kraft lignin.

A8: anionic lignosulfonate.

A1-based: Anionic Melamine-Formaldehyde-Sulfonate Poly Condensate.

A2-based: Anionic inorganic condensation polymer of silicic acid in the form of colloidal silica particles with a particle size of 5 nm.

Low molecular weight cationic organic polymers called ATC are either commercially available or made by known procedures. The ATC is as follows:

ATC: cationic copolymer (molecular weight 50,000) of dimethylamine, epichlorohydrin and ethylene diamine.

All polymers are used in the form of dilute polymer aqueous solutions.

Example 2

Dewatering performance is achieved by means of a dynamic drainage analyzer (DDA) (Akribi, Sweden), which measures the time it takes for a volume of stock to drain through the wire when the plug is removed and vacuum is applied to the wire side opposite the surface where the stock is present. Is evaluated.

Standard stock solutions are prepared from 56 wt% peroxide bleached TMP / SGW pulp (80/20), 14 wt% bleached birch / pine sulphate pulp (CSF 200 °) and a furnish based on 30 wt% China clay. To the stock solution is added 25 g / l colloidal parts, bleached water from a paper mill. The stock volume is 800 ml and the pH is 7. Calcium chloride is added to the stock solution to adjust the conductivity to 0.5 mS / cm. The obtained stock solution is called standard stock solution. Additional calcium chloride is added to the standard stock to prepare medium conductivity stock (2.0 mS / cm) and high conductivity stock (5.0 mS / cm).

During the test, the stock solution is stirred in a jar with baffles at a speed of 1500 rpm and the reagent addition is as follows: i) add a cationic polymer to the stock solution and stir for 30 seconds, ii) add anionic polymer to the stock solution and stir for 15 seconds, iii) Drain the stock solution and record the drain time. If ATC is used, add ATC to the stock solution and stir for 30 seconds before adding i) cationic polymer and ii) anionic polymer.

Table 1 shows dehydration (drainage) at various doses of cationic polymer C1 calculated as dry polymer for dry stock system and various doses of anionic polymer A1-based, A1 and A2 as dry polymer for dry stock system. ) Shows the effect. Standard stock solutions are used in Tests 1-5 and high conductivity stocks are used in Tests 6-9.

Test number Cl dose [kg / t] A dose [kg / t] Dehydration Time [s] A1-based A1 A2 123456789 303030303020202020 00.51.02.03.002.03.04.3 19.017.514.612.89.826.421.517.615.7 19.017.012.69.08.726.415.714.614.5 19.015.512.18.47.226.415.613.713.4

Example 3

The first pass retention performance was evaluated by means of a turbidimeter by measuring the turbidity of the white water obtained by draining the stock solution obtained in Example 2, a filtrate from a dynamic drainage analyzer (DDA). The results are shown in Table 2.

Test number Cl dose [kg / t] A dose [kg / t] Turbidity [NTU] A1-based A1 A2 1234 30303030 0.51.02.03.0 56555250 49504743 55504845

Example 4

Drainage performance is evaluated using the cationic and anionic polymers of Example 1 and the standard stock solutions and procedures of Example 2. The results are shown in Table 3.

Test number Cl dose [kg / t] A dose [kg / t] Dehydration Time [s] A1 A3 A4 1 2 3 4 5 020202020 001.02.04.0 18.012.510.910.310.0 18.012.510.09.08.7 18.012.510.28.98.0

Example 5

Drainage performance is evaluated using the cationic and anionic polymers of Example 1 and the intermediate conductivity stock solution and procedure of Example 2. The results are shown in Table 4.

Test number C dose [kg / t] A1 dose [kg / t] Dehydration Time [s] C1-based C1 C2 1234 10101010 00.751.53.0 13.812.612.814.1 14.610.69.510.1 11.57.46.67.2

Example 6

Drainage performance is evaluated using the cationic polymer and anionic polymer of Example 1 and the high conductivity stock solution and procedure of Example 2. The results are shown in Table 5.

Test number Cl dose [kg / t] A dose [kg / t] Dehydration Time [s] A2-standard A5 A6 1 2 3 4 5 2020202020 01.02.04.06.0 31.831.028.023.823.0 31.827.522.016.514.0 31.828.824.419.518.3

Example 7

Drainage performance is evaluated using the cationic polymer and anionic polymer of Example 1 and the high conductivity stock solution and procedure of Example 2. The results are shown in Table 6.

Test number C3 dose [kg / t] A dose [kg / t] Dehydration Time [s] A5 A6 1 2 3 4 5 22222 00.250.50.751.0 15.813.813.213.413.5 15.813.312.913.113.3

Example 8

Drainage and retention performance is assessed using the cationic and anionic polymers of Example 1 and the standard conductivity stocks and procedures of Examples 2 and 3. The results are shown in Table 7.

Test number C dose [kg / t] A7 dose [kg / t] Dehydration time / turbidity [s] / NTU C2-based C1 123 252525 024 22.0 / 4922.1 / 5021.2 / 46 23.4 / 4316.3 / 4014.3 / 40

Example 9

Drainage performance is evaluated using the cationic polymer, anionic polymer and Example ATC and the intermediate conductivity stock solution and procedure of Example 2 of Example 1. The results are shown in Table 8.

Test number ATC Dose [kg / t] C dose [kg / t] A7 dose [kg / t] Dehydration Time [s] C3-based C3 123 333 333 11.52 20.817.914.7 11.09.37.9

Example 10

Drainage and retention performance is assessed using the cationic polymer, anionic polymer, and ATC of Example 1 and the intermediate conductivity stock solution and procedure of Example 2. The results are shown in Table 9.

Test number ATC Dose [kg / t] C dose [kg / t] A8 dose [kg / t] Dehydration time / turbidity [s] / NTU C3-based C3 123 333 333 234 21.4 / 4917.4 / 4615.6 / 48 11.1 / 409.3 / 408.9 / 45

Example 11

Drainage performance is evaluated using the cationic polymer, anionic polymer of Example 1, and the standard conductivity stock solution and procedure of Example 2. The results are shown in Table 10.

Test number C dose [kg / t] A8 dose [kg / t] Dehydration time / turbidity [s] / NTU C2-based C1 1 2 3 4 5 2525252525 12468 23.0 / 4722.6 / 5022.8 / 4922.6 / 4922.1 / 50 20.8 / 4419.0 / 4318.8 / 4516.3 / 4015.5 / 42

Claims (19)

In the papermaking process from a suspension containing cellulose fibers and fillers comprising the steps of separately adding an anionic polymer having an aromatic group and a cationic polymer having an aromatic group to the suspension and forming and dehydrating the suspension on a wire, the anionic polymer is a condensation polymer. , Polysaccharides, natural aromatic polymers and modified products thereof, and if the anionic polymer is selected from the condensation polymer, it is not an anionic melamine-sulfonic acid condensation polymer. In the papermaking process from a suspension containing cellulose fibers and fillers comprising the steps of separately adding an anionic polymer having an aromatic group and a cationic polymer having an aromatic group to the suspension and forming and dehydrating the suspension on a wire, the anionic polymer is anionic Papermaking process characterized in that it is not polystyrene sulfonate or anionic melamine-sulfonic acid condensation polymer 3. The method of claim 1 or 2, wherein the cationic polymer is a cationic polysaccharide. 4. The method of claim 1, 2 or 3, wherein the cationic polymer is cationic starch. The papermaking process according to claim 1 or 2, wherein the cationic polymer is a vinyl addition polymerization polymer. 6. The method of claim 1, 2 or 5, wherein the cationic polymer is an acrylamide based polymer. The papermaking method of claim 1, wherein the cationic polymer has a weight average molecular weight of at least 1,000,000. The method of claim 1, wherein the cationic polymer has a benzyl group. The method of claim 1, wherein the anionic polymer is an anionic benzene-based or naphthalene-based condensation polymer. The method of claim 1, wherein the anionic polymer is prepared from aromatic compounds selected from phenyl, phenol, naphthalene, naphthol and derivatives and mixtures thereof. The papermaking method according to any one of claims 1 to 8, wherein the anionic polymer is a lignin based polymer. The method of claim 1, wherein the anionic polymer is a tannin extract, sulfonated lignin, benzene sulfonic acid based condensation polymer, benzene sulfonate based condensation polymer, xylene sulfonic acid based condensation polymer, xylene sulfonate, naphthalene sulfonic acid based condensation polymer, naphthalene sulfo Papermaking process characterized in that it is selected from Nate based condensation polymer, phenol sulfonic acid based condensation polymer, phenol sulfonate based condensation polymer and mixtures thereof The method of claim 1, wherein the anionic polymer is an anionic polyurethane. The papermaking process according to claim 1, wherein the anionic polymer has a weight average molecular weight of 500-1,000,000. The papermaking method of claim 1, wherein the cationic polymer is added in an amount of 0.005-2% by weight of the dry suspension. The method of claim 1, wherein the anionic polymer is added in an amount of 0.005-1.5% by weight of the dry suspension. The papermaking method of claim 1, further comprising adding a low molecular weight cationic organic polymer to the suspension. The method of claim 1, wherein the suspension has a conductivity of at least 2.0 mS / cm. The method of claim 1, further comprising recycling white water and introducing 0-30 tonnes of fresh water per tonne of paper produced.