DE102012012561A1 - Process for producing filled paper and cardboard using coacervates - Google Patents

Abstract

The invention relates to a process for the production of filled paper or cardboard, wherein an aqueous fiber suspension is produced, which contains cellulose fibers and at least one filler, and the fiber suspension is flocculated with a flocculation system, which comprises at least one inorganic microcomponent and a coacervate, which consists of at least one cationic polymer and one anionic polymer is formed, and the flocculated fiber suspension is processed into a filled paper or a filled cardboard.

Description

The invention relates to a process for producing filled paper or paperboard, wherein an aqueous fiber suspension is produced, which contains cellulose fibers and at least one filler, and the fiber suspension is flocculated with a flocculation system.

In industrial papermaking, sheet formation takes place on paper machines. Here, a cleaned and deaerated pulp, which consists of about 99% water and contains about 1% pulp fibers, formed in the headbox to a thin, uniform as possible beam. This is given in Langsiebpapiermaschinen on a rotating endless sieve. Within a few seconds most of the water runs off and it forms a paper structure. Fourdrinier machines can work up to a speed of about 1200 m / min. At higher speeds, paper formation is disturbed by air turbulence. Modern paper machines, so-called gap formers, produce at speeds of up to 2000 m / min at working widths of more than 10 m. Here, the pulp is injected directly into a gap between two rotating screens. In addition to the higher running speed, gap formers also offer the advantage of a significantly more even drainage and consequently a reduced two-sidedness of the paper. At the end of the screen, the soft paper web is transferred to a felt and enters the press section, where the paper web is dewatered by means of rollers pressed against each other between felts. Finally, in the dryer section, the final dewatering takes place, with the paper web passing through a number of steam-heated drying cylinders. Then the paper web is smoothed and rolled up. For highly smooth and sharply satined papers, another final smoothing step can be performed in the calender before final rolling up.

In addition to pulp fibers, the pulp or fiber suspension contains further constituents which influence the properties of the paper or its production process. Thus, the fiber suspension usually contains fillers in a proportion of up to 30 wt .-%, based on the fiber content. Suitable fillers are, for example, kaolin, talc, titanium dioxide, starch and calcium carbonate. Kaolin remains chemically inert over a wide pH range and therefore can be used in both acidic and alkaline production processes. Kaolin has been the most widely used pigment in the past. However, it has been increasingly replaced by calcium carbonate in recent years. Calcium carbonate has a higher whiteness compared to kaolin, which is particularly advantageous in the production of recycled paper. A distinction is made between ground calcium carbonate (GCC) and precipitated calcium carbonate (PCC). Ground calcium carbonate is made from CaCO ₃ -containing minerals such as limestone, chalk or marble. First, in a screening process, sludge and impurities such as colored silicates, graphite and pyrite are removed. The raw material is then further crushed and ground until the desired grain size is reached. GCC has a large brightness spectrum. If a high degree of brightness is required, mostly marble is used as starting material. GCC has replaced kaolin as the main filler pigment. Precipitated calcium carbonate is a synthetic industrial mineral made from quicklime or limestone. As a synthetic product, PCC can be modified in its properties to affect the properties of the paper. Thus, the reaction parameters set during the production of PCC can influence the grain size, the grain shape, the specific surface area and the surface chemistry as well as the particle size distribution. With PCC, therefore, the properties of the paper can be controlled, such as its brightness or its transparency, or the thickness of the paper layer. However, PCC can not be used indefinitely as a filler because it reduces fiber strength.

Fillers soften and soften the paper by filling in the gaps between the fibers, giving it a smooth surface. The mass fraction of the fillers is expressed in the ash number.

In addition to fillers, dyes and optical brighteners may also be present in the fiber suspension. Here mainly synthetic dyes are used. To make the paper writable, sizing agents are added. This makes the paper less absorbent and less hygroscopic. The sizing agents are chemically modified tree resins in combination with acid salts, such as potassium alum or aluminum sulfate. Polymers based on acrylates or polyurethanes are also used.

In the production of the paper web it is important that the water of the fiber suspension flows off quickly, without substantial amounts of fibers or fillers being discharged with the water and thus being lost. Furthermore, a stable paper structure should be formed.

For process optimization and to achieve specific paper properties additives are added to the fiber suspension in the course of the production chain. An important role is played by additives that contribute to increasing or improving the retention and drainage of papermaking. In retention, the objective is to retain as much of the filler as possible in the pulp. Drainage involves draining the suspension water as quickly as possible during sheet formation in the paper machine so that a dry sheet of paper can be formed quickly. Both objectives, high retention and rapid drainage, are closely related, and the improvement of one parameter should not be at the expense of the other.

Foliation is a very fast filtration process. Assuming a pure fiber suspension in which no special interactions between the fibers occur, formed during the filtration by the turbulent flow of a disordered nonwoven structure. The nonwoven here has disordered fluctuations, for example, in the paper thickness or basis weight. Contains the fiber suspension fillers, they are not retained during filtration of the sieve and therefore washed out with the outflowing water for the most part. The sheet would then contain no or only small amounts of filler in such a process management. The fiber suspension is therefore added with chemical additives which can interact with both the fibers and the filler particles. These interactions lead to the formation of larger aggregates of fibers and filler particles before filtration. The fiber suspension flocculates to form larger flocs in which fibers and filler particles are bound. Due to the chemical additive, usually a charged polymer, the flakes themselves contain a charge. However, these flakes have a low mechanical strength, so that they can be easily cut by the action of shearing forces.

Many retention and drainage systems have been developed in recent decades. The aim is to optimize retention and drainage independently of each other. One differentiates between two-component and multi-component retention and drainage systems.

In dual retention and drainage systems, a high molecular weight cationic polymer is added to the fiber suspension to precipitate the fibers in the form of flocs from the fiber suspension. After a possibly subsequent step, in which the flocculated suspension is subjected to shear forces, for example by stirring, to produce microflakes, a bentonite is added, which causes a combination of the flakes and, after separation of the water, the formation of a stable paper structure. It is desired that the bentonite is present in the strongest possible delaminated form, so that a high number of particles is available for connecting the flakes. The mixture is then placed on a sieve so that the water can run off and form a stable paper layer. Dual retention and drainage systems are often referred to as microparticle systems, and may also include, for example, a combination of one or more cationic polymers and anionically charged microparticles, such as anionically charged organic components, silica particles, or swellable clay materials. A commercial, available on the market dual retention and drainage system is for example the Hydrocol ^® system.

A dual retention and drainage system, for example, in the EP 0 235 893 B2 described. An aqueous cellulosic suspension is first flocculated with a substantially linear synthetic cationic polymer having a molecular weight of more than 500,000 g / mol. The cationic polymer is added in an amount of at least 0.03% by weight based on the dry weight of the suspension. The flakes formed by the addition of the polymer are broken by shearing to form microflakes which resist further degradation by shearing and carry sufficient cationic charge to interact with bentonite added to the suspension after shearing. The re-flocculated suspension is then processed into a paper web. As the cationic polymer, for example, polyethyleneimine, polyaminoepichlorohydrin products, polymers of diallyldimethylammonium chloride and polymers of acrylic monomers comprising a cationic acrylic monomer can be used. The bentonite is preferably added in delaminated form. It is preferably used as a hydrated suspension obtained by dispersing powdered bentonite in water. The bentonite is added in an amount of 0.03 to 0.5 wt .-%, based on the dry weight of the suspension. The cellulose fiber suspension may also contain a filler, such as calcium carbonate.

Multi-component systems, in addition to a high molecular weight cationic polymer and an anionic microparticle, such as a layered silicate or silica particles, also contain a highly crosslinked organic microparticle. With such a three-component system, not only the filler retention be significantly improved, but also the retention can be influenced independently of the drainage. This means that the filler retention can be varied with the third and possibly also a fourth component, without negatively affecting the drainage. A well-known multi-component system on the market is offered under the brand TELIOFORM ^®.

In the WO 02/33171 A1 describes a process for the production of paper or paperboard, wherein a pulp fiber suspension is precipitated with a flocculation system comprising, in addition to a cationic polymer and a silicate-containing material as a further component of organic microparticles which have a particle diameter of less than 750 nm in the non-swollen state. The microparticles consist of a highly crosslinked polymer and preferably carry an anionic charge. The microparticles can be prepared, for example, by microemulsion methods by reacting an aqueous solution of a cationic or anionic monomer and a crosslinking agent in the presence of a saturated hydrocarbon and a surfactant to produce particles of less than 0.75 μm in size. Polymerization to produce microparticles is initiated by the addition of an initiator or by irradiation of the emulsion with ultraviolet light. To control the chain length, a chain transfer agent can be added to the emulsion. Crosslinked organic polymeric microparticles have been found to have high efficacy as retention and drainage aids when their particle size is less than about 750 nm, preferably less than about 300 nm, and uncrosslinked organic water-insoluble polymer microparticles exhibit high potency when sized is less than 60 nm.

Improving filler retention and drainage speed is a constant challenge in papermaking. The tools used should be easy to represent and readily available, already show good efficacy in small quantities and allow an independent influence on parameters such as drainage and filler retention.

The invention therefore an object of the invention to provide a process for the production of filled paper or paperboard, which can be carried out economically and requires only small amounts of readily available excipients.

This object is achieved by a method having the features of patent claim 1. Advantageous embodiments of the method are the subject of the dependent claims.

In the method according to the invention a coacervate is used as auxiliary component, which is formed from at least one cationic polymer and an anionic polymer. The cationic polymer and the anionic polymer are not bound by covalent bonds in the coacervate but are separately present as individual components. In the coacervate, cationic and anionic polymers are held together by electrostatic forces and possibly steric effects in a complex to form an organic microparticle that has multiple constituents that are not bound together by covalent bonds. The charge of the coacervate may be adjusted by the charge of its constituents, cationic polymer and anionic polymer, as well as by the ratio in which the polymers are contained in the coacervate. The coacervates form stable microparticles so that an emulsion or dispersion of the coacervate in water can be stable for several days. The use of coacervates significantly improves both the drainage properties and the filler retention, so that the papermaking process can be carried out economically efficiently. By varying the coacervate composition, the parameters of drainage and filler retention can be influenced so that a further improvement of the papermaking process is possible. In particular, it has been found that coacervates are excellent flocculants for fillers, especially calcium carbonate, and thus can produce significant improvements in filler retention in papermaking without negatively affecting drainage properties.

According to the invention, therefore, there is provided a process for producing filled paper or paperboard, wherein an aqueous fiber suspension containing fibers and at least one filler is prepared and the fiber suspension is flocculated with a flocculation system comprising as components at least one inorganic microcomponent and a coacervate which is formed from at least one cationic polymer and an anionic polymer, and the flocculated fiber suspension is processed into a filled paper or paperboard.

The inventive method for producing filled paper and paperboard is carried out per se analogously to conventional such methods, but wherein the fiber suspension in the flake in addition to the inorganic microcomponent, for example a silicate material, a coacervate is added as an additional aid.

The process according to the invention is based on an aqueous suspension which is preferably 0.1 to 10% by weight, more preferably 0.4 to 3% by weight and, according to a further embodiment, 0.6 to 1.5% by weight. Contains fibers.

The fibers used are preferably a cellulose fiber material. Such a cellulose fiber material can be obtained in the usual way by chemical pulping of wood or annual plants. The pulp fibers consist predominantly of cellulose and may still contain small amounts of polyoses or lignin. As a fiber material, however, for example, a recycled material from waste paper can be used. Likewise, mixtures of such materials may be used.

Furthermore, the suspension, based on the content of fibers, preferably contains up to 40% by weight, according to one embodiment, of 5 to 35% by weight of fillers. Fillers which can be used in papermaking are customary fillers, with inorganic fillers being preferred. Suitable fillers are, for example, titanium dioxide, natural or precipitated chalk (calcium carbonate), talcum, kaolin, satin white, calcium sulfate, barium sulfate, clays or aluminum oxide. The fiber suspension preferably passes through at least one cleaning, mixing and / or pumping stage. The shearing of the fiber suspension can take place, for example, in a pulper, classifier or in a refiner. Preferably, the coacervate is added after the last shear stage. Subsequently, the flocculated fiber suspension is poured onto a sieve for sheet formation.

The inorganic microcomponent of the flocculation system may be added along with the coacervate after the last shear stage. However, it is also possible first to add the inorganic microcomponent, then preferably to shear the pulp again and only then to add the coacervate. Preferably, however, proceeding in such a way that inorganic microcomponent and coacervate are added after the last shear stage. The addition of inorganic microcomponent and coacervate may be simultaneous or sequential. According to a particularly preferred embodiment, first the inorganic microcomponent is added and then the coacervate.

Suitable inorganic microcomponents of the flocculation system are, for example, bentonite, colloidal silicic acid, silicates and / or calcium carbonate. The particle size of the inorganic microcomponent is preferably chosen to be very small and is preferably less than 200 .mu.m, according to a further embodiment less than 150 .mu.m and according to a further embodiment is preferably in the range from 10 nm to 100 .mu.m. The size of the microparticles refers to the mean size D _{50 of} the microparticles and is preferably determined by optical methods such as light scattering and indicates the number-average value. Preferably, at least 50% of the particles have a size in the range of ± 30% of the mean. The inorganic microcomponent preferably has an anionic charge such that it can interact with fiber flakes, which preferably have a cationic excess charge.

Silicates are to be understood as meaning products based on silicates or silicic acid, for example silica microgels, silica sols, polysilicates, aluminum silicates, borosilicates, polyborosilicates, clays or zeolites. Calcium carbonate can be used, for example, in the form of chalk, ground calcium carbonate or precipitated calcium carbonate as the inorganic microcomponent of the flocculation system. Bentonite is generally understood to be layered silicates which are swellable in water. Particular preference is given to montmorillonite or bentonites having a high montmorillonite content, for example having a montmorillonite content of more than 50% by weight. Clay minerals similar to bentonite may also be used, such as nontronite, hectorite, saponite, sauconite, beidellite, alevardite, illite, halloysite , Attapulgite and sepiolite. These phyllosilicates are preferably activated for use, that is, converted into a water-swellable form by treating the phyllosilicates with an alkali metal salt, for example soda. Layered silicates, in particular bentonite, are preferably used as the inorganic microcomponent.

The inorganic microcomponent is preferably added in the form of a suspension to the fiber suspension. The suspension preferably has a solids content in the range from 0.5 to 10% by weight, preferably from 1 to 5% by weight. When phyllosilicates are used as the inorganic microcomponent, the phyllosilicate is preferably used in as completely as possible a delaminated form. The platelet diameter of the layered silicate dispersed in the water is preferably in the range of 1 to 2 μm, the thickness of the platelets is preferably 0.1 to 10 nm, in one embodiment in the range of 1 to 5 nm. The bentonite preferably has a specific surface area in the Range from 60 to 800 m ² / g. The Determination of the specific surface can be after DIN 66131 be determined by means of nitrogen porosimetry.

As the colloidal silica or silicates, there may be used products of the group of silicon-based particles, silica nitrogels, silica sols, aluminum silicates, borosilicates, polyborosilicates or zeolites. These materials typically have a specific surface area in the range of 50 to 1000 m ² / g and an average particle size distribution of 1 to 250 nm, for example in the range of 40 to 100 nm.

Silica materials, particularly preferably phyllosilicates and particularly preferably bentonites, are preferably used as the inorganic microcomponent.

The inorganic microcomponent of the flocculation system is added to the aqueous fiber suspension preferably in an amount of from 0.01 to 1.0% by weight, more preferably in an amount of from 0.1 to 0.5% by weight, based on the solid content of the fiber suspension ,

The flocculated fiber suspension is then processed in the usual way to a paper or cardboard. This can be poured, for example, preferably without further action of shear forces on a sieve under sheet formation. The paper sheets are then dried.

In addition to the flocculation system, the fiber suspension can be added to the process chemicals commonly used in papermaking in conventional amounts, such as fixatives, dry and wet strength agents, engine sizes, biocides, and / or dyes.

The coacervate used in the manufacture of filled paper or board according to the invention may be neutral, but it is preferred that the coacervate has an excess charge. The excess charge can be generated by one of the two polymers used for the preparation having a higher charge than the oppositely charged polymer. This can be achieved, for example, by one of the polymers having a higher molecular weight for the same percentage of charged monomer units or by one of the two polymers having a higher percentage of charged monomers at the same molecular weight. Mixed forms of these embodiments are also possible. The percentages refer in each case to the entirety of the monomer units contained in a polymer, for example acrylate or acrylamide units, which are derived from the corresponding monomers, for example acrylates or acrylamides. The charge of the coacervate is determined by the polymer used in excess in relation to its charge. According to the inventors' model, the charge-in-excess polymer forms the core of the coacervate, while the excessively charged groups present on the outside of the coacervate. Preferably, the coacervate has an anionic excess charge.

According to one embodiment, anionic and cationic polymers are in a charge ratio in the range of 0.1 to 0.95, according to another embodiment in the range of 0.2 to 0.7 and according to yet another embodiment in the range of 0.2 to 0 5 contained in the coacervate. The charge ratio is determined by the ratio of the charged groups in the one polymer to the charged groups in the other, oppositely charged polymer. When one or both of the charged polymers have a molecular weight distribution, the ratio refers to the average number of charged groups per each polymer, reference being made to the number average.

As already stated, the coacervate may have a positive or a negative excess charge. Accordingly, the anionic or cationic polymer may be contained in the coacervate in excess. At the above ratio, both the anionic and the cationic polymer may be present in excess. Preferably, the anionic polymer is present in excess.

The process is preferably carried out by first preparing an aqueous dispersion of the coacervate and then adding the aqueous dispersion of the coacervate to the aqueous fiber suspension. The fiber suspension can already be present in a flocculated state. The flocculation of the fibers may have been effected, for example, by the addition of the inorganic microcomponent.

Preferably, the coacervate is added in the form of an aqueous dispersion. To prepare the coacervate dispersion, anionic and cationic polymers are added to an aqueous solvent, which can be added both sequentially and simultaneously. After the addition of anionic and cationic polymer, which preferably takes place with stirring, a turbidity forms. Particularly advantageous results in terms of drainage and retention are obtained when the aqueous dispersion of the coacervate remains stable for a long time and, for example, no flocculation occurs during storage. The storage is preferably carried out at room temperature. The coacervate dispersion is preferably adjusted so that the turbidity of the dispersion remains stable for at least six days. If the coacervate flocculates prematurely, the turbidity stability can be adjusted, for example, by the ratio of anionic and cationic polymer or by the concentration of coacervate in the aqueous dispersion. The flocculation of the sample can be visually detected as the flocs fall and the supernatant solution becomes clear. Possibly. For example, the stability of the dispersion can also be measured by measuring the turbidity by absorption at a wavelength of 500 nm.

According to a preferred embodiment, the coacervate dispersion has a content of coacervate in the range from 0.1 to 15% by weight, preferably 0.2 to 2% by weight, in another embodiment in the range from 0.25 to 0, 3 wt .-% on. The content of coacervate can be calculated from the amount of anionic and cationic polymer added to the aqueous solvent. After the addition of the anionic polymer and the cationic polymer to the aqueous solvent, the dispersion is preferably agitated for a period of at least 10 minutes, preferably at least 30 minutes, more preferably at least one hour, so that the coacervates can form. The preparation of the coacervates preferably takes place at room temperature. According to one embodiment, the preparation of the coacervate is carried out at a temperature of more than 10 ° C, according to another embodiment of more than 15 ° C. In one embodiment, the coacervate is produced at a temperature of less than 30 ° C.

In order to facilitate the formation of the coacervate or to stabilize the dispersion of the coacervate, it is provided according to one embodiment that the dispersion of the coacervate contains an electrolyte. A suitable electrolyte are salts of monovalent cations, more preferably of alkali metal cations. A particularly preferred electrolyte is sodium chloride. The concentration of the electrolyte in the dispersion of the coacervate is preferably selected in the range of 0.1 to 2 wt .-% according to another embodiment in the range of 0.2 to 1 wt .-%. In the preparation of the dispersion of the coacervate is preferably carried out in such a way that first the electrolyte is dissolved in the aqueous solvent and then the cationic and the anionic polymer is added.

According to the inventors, the coacervate comprises a core composed of the one charged polymer and a shell disposed around the core and which is formed by the oppositely charged polymer. In order to facilitate formation of the coacervate, it is provided according to one embodiment that at least one of the at least one cationic and at least one anionic polymer contained in the coacervate has a linear structure. Preferably, at least that polymer has an uncrosslinked, linear structure which generates the excess charge and thus determines the charge of the coacervate. The deficit-containing polymer may also have a crosslinked structure. However, it is preferred that both charged polymers have a linear structure. A linear structure is understood as meaning a structure in which the polymer has as a backbone a linear carbon chain which, however, may optionally also contain heteroatoms, such as oxygen or nitrogen atoms.

In order to be able to provide stable coacervates it is preferred that the cationic polymer or the anionic polymer has a certain chain length or a certain molecular weight. According to one embodiment, it is provided that the coacervate-forming at least one cationic polymer and the at least one anionic polymer each have a molecular weight of more than 50,000 g / mol. According to a further embodiment, it is provided that the at least one cationic polymer and / or the at least anionic polymer have a molecular weight of more than 100,000 g / mol, according to another embodiment, a molecular weight of at least 200,000 g / mol. According to a further embodiment, it is provided that the cationic polymer and / or the at least one anionic polymer has a molecular weight of less than 3,000,000 g / mol. The molecular weight of anionic polymer and cationic polymer may be the same or different. According to one embodiment, it is provided that the molecular weight of the one polymer is significantly greater than the molecular weight of the oppositely charged polymer. According to one embodiment, the one polymer has a molecular weight of at least 500,000 g / mol, according to another embodiment, a molecular weight of at least 1,000,000 g / mol, while the molecular weight of the oppositely charged polymer is preferably selected in the range of 100,000 to 500,000 g / mol.

The cationic polymer according to one embodiment comprises uncharged monomer units as well as cationic monomer units. Monomer units are understood to mean in each case repeating units contained in the polymer, which are derived from the monomers used to prepare the polymer. Uncharged monomer units do not include a group carrying a charge. Cationic or anionic monomer units accordingly comprise a group carrying a cationic and an anionic charge, respectively.

Cationic monomer units preferably comprise a nitrogen-containing group which receives a permanent positive charge either by protonation or by alkylation.

The cationic polymer according to one embodiment comprises cationic monomer units, wherein the proportion of the cationic monomer units in the entirety of the cationic polymer-forming monomer units according to one embodiment at least 2 mol% according to another embodiment at least 5 mol% and according to yet another embodiment at least 10th mol%. According to a further embodiment, the proportion of the cationic monomer units based on the total number of monomer units of the cationic polymer is at least 20 mol%, according to a further embodiment at least 30 mol%.

The cationic polymer can only be composed of cationic monomer units. According to a further embodiment, the proportion of the cationic monomer units in the entirety of the cationic polymer-forming monomer units is less than 80 mol%, in another embodiment less than 60 mol%. According to a further embodiment, the proportion of the cationic monomer units contained in the cationic polymer is less than 50 mol%, according to yet another embodiment less than 40 mol%.

Suitable cationic monomers from which the cationic monomer units are derived are compounds having an unsaturated carbon-carbon double bond and a positively charged group. The positively charged group may already be present in the monomer or be generated or introduced into the polymer only after the polymerization of the carbon-carbon double bond by a corresponding modification in the polymer. Such a modification would be, for example, the alkylation or protonation of an amino group.

Suitable monomers which can be given a positive charge by protonation or alkylation are, for example, N, N-dialkylaminoalkyl (meth) acrylamides and N, N-dialkylaminoalkyl (meth) acrylates. The alkyl groups on the nitrogen atom preferably comprise 1 to 4 carbon atoms. Particularly preferred are the methyl and the ethyl group. Exemplary monomers are 2- (dimethylamino) ethyl acrylate, 2- (diethylamino) propyl acrylate, 2- (dimethylamino) ethyl methacrylamide, 2- (diethylamino) ethyl acrylamide, 2- (diethylamino) propyl methacrylamide.

The cationic polymer preferably contains monomer units which carry a permanent positive charge by alkylating the nitrogen atom. Suitable monomers are, for example, (meth) acrylamidoalkyltrialkylammonium halides and (meth) acryloxyalkyltrialkylammonium halides. The alkyl groups on the nitrogen atom may be the same or different and preferably comprise 1 to 4 carbon atoms. The alkyl group is particularly preferably selected from the methyl group and the ethyl group. The alkyl group of the alkylamino group preferably comprises 1 to 12 carbon atoms, preferably 1 to 4 carbon atoms, and is more preferably a methyl, ethyl or a propyl group. Exemplary suitable monomers are 3-acrylamidopropyltrimethylammonium chloride and acryloxyethyltrimethylammonium chloride.

Generally, as monomers having a cationic group, compounds of the formula I are suitable.

Formel I

Formula I

Where:
R ¹ : H, CH ₃
R ^{2 is} H, C ₁ -C ₄ -alkyl
R ³ , R ⁴ : H, C ₁ -C ₂ alkyl, aryl or hydroxyethyl
X: O, NR ¹
A: alkylene of 1 to 12 carbon atoms,
wherein at least two groups of R ² , R ³ , R ^{4 are} not H and in the case that R ² , R ³ and R ^{4 are} alkyl groups, they may be the same or different.

Further suitable as cationic monomers are diallyldialkylammonium halides, where the alkyl groups may be identical or different and may comprise from 1 to 4 carbon atoms. Particularly preferred is poly-DADMAC:

The cationic groups are preferably in the form of their halides. The halides include fluorides, chlorides, bromides and iodides, with chlorides being particularly preferred.

Uncharged monomers which may be present in the cationic polymer include, for example, alkyl (meth) acrylates and also (meth) acrylamides or other uncharged ethylene compounds.

The cationic polymer is particularly preferably selected from the group of polyacrylamides, polyethyleneimines, polyvinylamines, polyethylene glycols, poly-DADMAC, and also native polymers, such as cationic starch or chitosan.

Examples of suitable cationic polymers are polyamine / epichlorohydrin polymers and also homopolymers or copolymers of acrylamide and, for example, diallyldimethylammonium chloride.

The anionic polymer contained in the coacervate comprises anionic monomer units, wherein the proportion of the anionic monomer units in the entirety of the anionic polymer-forming monomer units according to one embodiment at least 2 mol%, according to another embodiment at least 5 mol% and according to yet another embodiment at least 10 mol%. According to a further embodiment, the proportion of the anionic monomer units based on the total number of monomer units of the anionic polymer is at least 20 mol%, according to a further embodiment at least 30 mol%. In a further embodiment, the proportion of the anionic monomer units in the entirety of the anionic polymer-forming monomer units is less than 50 mol%, in another embodiment less than 40 mol%.

The anionic polymer can only be composed of anionic monomer units. In a further embodiment, the proportion of the anionic monomer units in the entirety of the anionic polymer-forming monomer units is less than 80 mol%, according to another embodiment, less than 60 mol%. According to a further embodiment, the proportion of anionic Polymer contained anionic monomer units less than 50 mol%, according to yet another embodiment, less than 40 mol%.

Suitable anionic monomers or monomer units are compounds having an unsaturated carbon-carbon double bond and a negatively charged group. Exemplary anionic monomers are (meth) acrylic acid, 2-acrylamido-2-methylpropanesulfonate, sulfoethyl (meth) acrylate, vinylsulfonic acid, styrenesulfonic acid and maleic acid. The enumeration of the anionic monomers should not be understood as exhaustive but merely as an example.

The anionic groups of the anionic monomer units of the anionic polymer can be introduced into the polymer already in the polymerization of the monomers for the preparation of the anionic polymer. However, it is also possible for the anionic groups of the anionic monomer units to be introduced into the anionic polymer only after the polymerization, for example by saponification of an ester group present in the polymer.

The anionic monomers can be copolymerized with neutral monomers to the anionic polymer. Exemplary neutral monomers are (meth) acrylamide, N-alkylacrylamides, such as N-methylacrylamide, alkyl (meth) acrylates, such as methyl (meth) acrylate.

According to a preferred embodiment, the anionic polymer is selected from the group of polyacrylates, polyacrylamides, as well as copolymers of acrylates and acrylamides, anionic starches, cellulose derivatives, such as caboxymethyl, ethyl, propylcelullose, cellulose ethers, alginates, carrageenans, wherein these polymers are each anionic groups exhibit.

According to a preferred embodiment, anionic and cationic polymers are selected from the group of poly (meth) acrylates and poly (meth) acrylamides, whereby mixed polymers are also suitable, these polymers comprising anionic or cationic monomer units.

The process according to the invention produces filled papers or paperboards. As fillers, the fillers known from the production of paper or paperboard can be used per se. According to a preferred embodiment, the filler is selected from calcium carbonate, which may be in precipitated or ground form, clays, titanium dioxide, talc, kaolin, magnesium carbonate, barium sulfate, zinc sulfide and calcium silicates.

The filler preferably has a particle size (D ₅₀ ) of less than 10 μm, preferably less than 5 μm, and according to a further embodiment has a particle size of less than 1 μm. According to one embodiment, the average particle size D _{50 of} the filler is at least 10 nm, according to a further embodiment at least 100 nm. According to one embodiment, the filler particles have a size (D ₁₀₀ ) of less than 1 mm, according to a further embodiment of less than 500 μm and according to another embodiment of less than 300 microns. The values refer to number-average values.

The proportion of the filler is chosen according to one embodiment less than 50 wt .-%, according to another embodiment, less than 40 wt .-% and according to another embodiment, less than 30 wt .-%, and in one embodiment more than 1 wt .-%, according to another embodiment more than 10 wt .-%, according to yet another embodiment more than 20 wt .-%. The percentages are based on the dry weight of the fiber suspension.

Particularly preferably, calcium carbonate is used as filler. As calcium carbonate, natural calcium carbonate (ground calcium carbonate, GCC) or precipitated calcium carbonate (PCC) can be used. GCC is produced by milling and visual processes using grinding aids. The specific surface area is preferably in the range of 6 to 2 m ² / g. PCC is made by passing carbon dioxide into calcium hydroxide solution. The values are based on the particle number. The specific surface area can be greatly influenced by the choice of precipitation conditions. It is preferably in the range of 6 to 13 m ² / g.

According to a particularly preferred embodiment, in addition to the inorganic microcomponent and the coacervate, the flocculation system comprises at least one further flocculation component which is selected from at least one further anionic polymer and at least one further cationic polymer.

As such, neutral polymers can also be used as further flocculation component. However, charged polymers are preferred. An exemplary nonionic or neutral polymer which can be used as further flocculation component is polyacrylamide, which preferably has a molecular weight between 500,000 and 7,000,000 g / mol. Polyacrylamides can be prepared by homopolymerization of acrylamide.

The polymers of the further flocculation component are added individually, that is, either only anionic polymer is added or only cationic polymer. The polymers used as further flocculation component are thus not present in the form of a coacervate. According to one embodiment, the polymer used as an additional flocculation component has an overall charge whose sign is opposite to the total charge of the coacervate. In terms of amount, the total charges of the polymer used as an additional precipitating component and the coacervate are generally different. Preferably, cationic polymers are added as an additional precipitation component.

The addition of the polymers used as additional precipitation component causes a flocculation of the fiber suspension, which can form relatively large and loose flakes. The amount of the anionic or cationic polymer is chosen so that the flakes receive an anionic or cationic total charge.

Essentially cationic polymers can be used as further precipitation component, as they have already been mentioned above as part of the coacervate.

Anionic polymers can also be used as further precipitation component, in which case it is likewise possible to use anionic polymers, as already mentioned above as part of the coacervate.

The polymers used as further flocculation component are preferably substantially linear and, according to one embodiment, have a molecular weight of more than 500,000 g / mol, preferably a molecular weight of more than 1 × 10 ⁶ g / mol and according to another embodiment, a molecular weight of more than 5 × 10 ⁶ g / mol. According to a further embodiment, the molecular weight of the polymer used as further flocculation component is less than 5 × 10 ⁸ g / mol.

Polymers usually show no uniform molecular weight but have a molecular weight distribution. The molecular weight data refers to the number average molecular weight of the polymer. The molecular weight can be determined, for example, with the aid of size exclusion chromatography in comparison with standards.

The amount of the polymer used as a further flocculation component, preferably cationic polymer, based on the dry mass of the fiber suspension, according to a preferred embodiment greater than 0.03 wt .-% selected. According to a preferred embodiment, the amount of added as a further flocculation polymer is less than 0.5 wt .-%, according to another embodiment, less than 0.2 wt .-%. According to a preferred embodiment, the amount of polymer added as a further component of the flocculation system is selected in the range of 0.06 to 0.15, in another embodiment in the range of 0.07 to 0.12 wt .-%.

Cationic polymers suitable as additional flocculation component are, for example, polyethyleneimines, which can also be further crosslinked by grafting polyethylene glycol bis-chlorohydrin ethers onto the free secondary amino groups. Also suitable are polyvinylamines.

Preferred cationic polymers are, for example, dialkylaminoalkyl (meth) acrylates and dialkylaminoalkyl (meth) acrylamides which are added in protonated form or in the form of a quaternary ammonium salt. The alkyl groups bonded to the nitrogen atom preferably comprise 1 to 4 carbon atoms. Most preferably, the alkyl group is selected from methyl group and ethyl group. The aminoalkyl group according to a preferred embodiment comprises 1 to 8 carbon atoms. Particular preference is given to using dialkylaminoethyl (meth) acrylate, dialkylaminomethyl (meth) acrylate and dialkylamino-1,3-propyl (meth) acrylates. To generate a permanent cationic charge, the nitrogen atom of the amino group is preferably alkylated with a methyl or an ethyl group. The cationic monomers are preferably copolymerized with neutral monomers, for example (meth) acrylamide or alkyl (meth) acrylates, such as methyl (meth) acrylate.

As anionic polymers it is possible to use the anionic polymers already mentioned above.

In the production of paper and paperboard, preference is given to initially providing an aqueous fiber suspension which preferably has a solids content of more than 0.5% by weight and more than 1% by weight according to a further embodiment a still further embodiment has a solids content in the range of 1 to 3 wt .-%.

To the fiber suspension, the polymer used as further component of the flocculation system, preferably a cationic polymer, is preferably added first. The addition of the preferably cationic polymer causes flocculation of the fiber suspension, forming relatively large and loose flocs. This large flake suspension is then preferably subjected to shear forces, thereby splitting the large flakes into microflakes which resist further exposure to shear forces.

After preparation of the microflakes, the suspension is preferably no longer exposed to high shear forces. Subsequently, the addition of the further components of the flocculation system, ie. H. the inorganic microcomponent as well as the coacervate.

The addition of the components of the flocculation system is carried out sequentially according to a preferred embodiment. Preferably, first the inorganic microcomponent and then the coacervate are added to the fiber suspension.

According to a particularly preferred embodiment, an aqueous fiber suspension is initially prepared which contains fibers, preferably cellulose fibers, and at least one filler. The fiber suspension is then flocculated first by addition of a polymer, preferably a cationic polymer, which serves as a further component of the flocculation system. The resulting large flakes are cut into microflakes by exposing the flocculated fiber suspension to shear forces. This can be done for example by mixing.

For the suspension of the microflakes, the inorganic microcomponent, preferably a bentonite, which particularly preferably has a high swellability, is then added. The amount of the inorganic microcomponent, preferably the amount of bentonite, is preferably in the range of 0.03 to 0.5 wt .-% according to another embodiment in the range of 0.05 to 0.3 wt .-% and according to yet another Embodiment selected in the range of 0.08 to 0.2 wt .-%. The percentages are based on the dry weight of the fiber suspension. The addition of the inorganic microcomponent preferably takes place in the form of an aqueous suspension, which particularly preferably has a solids content in the range from 1 to 10% by weight. After the addition of the inorganic microcomponent, the flocculated suspension is preferably no longer sheared. The addition of the coacervate is then carried out and then the flocculated suspension is poured out in a customary manner onto a sieve in order to produce a paper structure. The paper structure is then processed in the usual way to a paper or a cardboard. For this purpose, methods known to the person skilled in the art can be used.

The invention will be explained in more detail below by means of examples and with reference to the accompanying figures. Showing:

1 : the flocculation behavior of sample 13 as a function of time, determined for different ratios of polymeric anion / polymer cation by determination of the absorption at a wavelength of 500 nm;

2 the flocculation behavior of the sample 220 as a function of time, determined for different ratios of polymeric anion / polymer cation by determination of the absorption at a wavelength of 500 nm; Addition of the coacervate occurs at 1412 s after the absorption of the PCC has stabilized;

3 : the flocculation behavior of samples 205 and 210 as a function of time, determined by determination of the absorption at a wavelength of 500 nm;

4 : a representation of the flocculation time T ₅₀ for different coacervates; the measurement was carried out for different ratios of polymeric anion / polymeric cation;

5 : a representation of the flocculation index as a function of the charge of the investigated coacervate;

6 : The results of drainage tests

Measurement Methods:

Determination of the molecular weight of the polymers:

The molecular weight of the polymers is determined by size exclusion chromatography and comparison with standard polymers.

Determination of the particle size distribution

The particle size distribution is determined by light scattering with commercially available Zetasizers (3000 HS, Zetamaster S, Malvern Instruments) according to the manufacturer's instructions.

The detected laser light scattering of sufficiently diluted suspension allows a temporal distribution of the laser intensity, which correlates with the particle size or particle size distribution.

Determination of the zeta potential

The zeta potential is determined by means of laser Doppler anemometry (LDA). The electrophoretic migration rate of colloids or coacervates is measured in suspension. From this colloid speed can be concluded that the zeta potential.

The Zetamaster S (Malvern Instruments) and the Zetasizer 3000HS (Malvern Instruments) were used.

Specific surface and pore radius distribution

The specific surface area was measured by the BET method (one-point method using nitrogen according to DIN 66131 , Multipoint determination) using an automatic nitrogen porosimeter (Micromeritics, type ASAP 2010). The pore volume was determined by the BJH method ( EP Barrett, LG Joyner, PP Hienda, J. Am. Chem. Soc. 73 (1951) 373 ) certainly. Pore volumes for certain pore radius ranges were determined by summing up incremental pore volumes, which were determined from the adsorption isotherm by BJH. The total pore volume refers to pores with a diameter of 2 to 7500 nm

montmorillonite

Determination of montmorillonite content via methylene blue adsorption

The methylene blue value is a measure of the inner surface of the clay materials.

a) Preparation of a tetrasodium diphosphate solution

5.41 g tetrasodium diphosphate are weighed to 0.001 g exactly in a 1000 ml volumetric flask and shaking to the mark with dist. Water filled up.

b) Preparation of a 0.5% methylene blue solution

In a 2000 ml beaker, 125 g of methylene blue in about 1500 ml dest. Water dissolved. The solution is decanted off and distilled to 25 l with dist. Water filled up.

0.5 g of wet test bentonite with a known internal surface are weighed to the nearest 0.001 g in an Erlenmeyer flask. Add 50 ml of tetrasodium diphosphate solution and heat the mixture to boiling for 5 minutes. After cooling to room temperature, 10 ml of 0.5 molar H ₂ SO _{4 are} added and 80 to 95% of the expected final consumption of methylene blue solution is added. With the glass rod, a drop of the suspension is taken and placed on a filter paper. It forms a blue-black spot with a colorless yard. It is then added in portions of 1 ml more Methylenblaulösung and repeated the dot sample. The addition takes place until the yard turns slightly light blue, so that the added Methylenblaumenge is no longer absorbed by the test bentonite.

c) Testing of clay materials

The test of the clay material is carried out in the same way as for the test bentonite. From the used amount of methylene blue solution, the inner surface of the clay material can be calculated.

381 mg methylene blue / g clay correspond to a content of 100% montmorillonite according to this method. Production of coacervates

a) Preparation of polymer solutions

General manufacturing instructions

Preparation of polymer stock solutions

Of the polymers listed in Table 1, a polymer stock solution was prepared in each case, in a concentration of 1 g of polymer / L solution, dissolved in optionally dist. Water or brine (0.2 M aqueous NaCl) adjusted to pH 7 with HCl or NaOH.

b) Production of coacervates

Coacervates were prepared by mixing together stock solutions of the cationic and anionic polymers in specific volume ratios in 50 ml volume sample jars. The coacervates were prepared per polymer combination, each with three polymer ratios. Since the molecular weight was not known for all polymers, the ratios were set in mPK / mPA (volume amount). For the preparation of each 4 ml of coacervate solution, the amounts were mixed as indicated in Table 2, always adding the cation to the excess anion solution. Table 2: volumes of polymer stock solutions used for the preparation of coacervates number Polycation volume Polyanion volume relationship [.Mu.l] [.Mu.l] [PKation / Panion] 1 1590 2410 0.66 2 992 3005 12:33 3 667 3335 0.2

There were two batches each. Deionized water was used to make the first batch. The other batch was prepared using 0.2 M aqueous NaCl solution.

The sealed 50 ml test tubes were moved overnight on a shaker. After complete dissolution, the samples were outgassed at 40 ° C by ultrasound.

For the retention and drainage experiments, the coacervates summarized in Table 3 were selected. Table 3: Coacervates for retention and drainage experiments sample polyanion polycation Charge Ratio [Cation / Anion] Concentration [g / l] 013K FP 3230 S FO 4290 PG 2 0.5 1 (0.1%) 0.4 0.3 0.2 205K FROM 995 V Alcofix 0.66 10 (1%) 210K Sokalan CP 45 Alcofix 12:33 10 (1%) in 0.2 M NaCl 220K Satialgine S 1600 FO 4190 PG 1 0.5 10 (1%) in 0.2 M NaCl 0.4 0.3 0.2

Of the coacervates listed in Table 3, the particle size or particle size distribution was determined by means of a Zetasizer. From each sample, 2 determinations were made with 3 measurements each. In each case the measurement was used for the evaluation, which had the lowest polydispersity index. Table 4 shows in each case the values for the maxima of the particle size distribution. The evaluation was determined by volume, ie the percentage of coacervates formed in the given volume. Table 4: Particle size distribution of coacervates sample PK / PA mass charge Peak evaluation (in terms of volume), mean value in nm PDI peak area Mean width 13 0.66 1 1.5 742.7 414.7 1,000 0.31 2 98.2 5,407.4 2,563.9 205 0.66 1 64.8 468.1 228.8 1,000 0.38 2 35.2 1,277.6 726.3 1,000 210 0.33 1 39.5 22.3 8.9 0.195 0.18 2 60.5 208.9 98.4 220 0.66 1 3.0 56.6 12.4 1,000 0.16 2 4.9 685.6 358.3 3 92.1 3,369.9 1,856.1 PDI: polydispersity index
PK: cationic polymer
PA: anionic polymer

Stability of coacervate dispersion / turbidity evaluation

The samples listed in Table 3 were stored in vials sealed for 6 days at room temperature. The stability of the coacervates was assessed after preparation of the coacervates and then daily. The evaluation listed in Table 5 was used. Table 5: Standard of evaluation for the assessment of the stability of coacervates value Status 0 Clear 1 cloudy 2 Flocculation / threads 3 lump 4 Flakes + lumps 5 Turbid + flakes 6 Cloudy + lumps

The evaluation of the stability measurements is summarized in Table 6. Table 6: Stability of coacervate dispersion as a function of time sample PK / PA charge 10 minutes day 2 Day 3 Day 6 13 0.2 1 1 0 1 0.33 1 1 1 1 0.66 1 1 1 1 205 0.66 1 1 1 1 210 0.33 0 0 0 0 220 0.2 1 0 0 0 0.33 1 1 1 2 0.66 1 1 1 0

Determination of the zeta potential

Selected samples were used to determine the zeta potential. The values determined are summarized in Table 7. Table 7: Zeta potential of selected samples sample PK / PA (charge) NaCl (M) Zeta potential [mV] 13 0.2 0.0 -56.1 205 0.66 0.0 -69.4 210 0.33 0.2 -11.9 220 0.2 0.2 -39.2 0.33 0.2 -30.8 0.66 0.2 -23.0

The zeta potentials of the coacervates are all anionic, but distinct differences occur. Since the pH of the samples was adjusted, the samples were measured directly. Measurements on samples containing NaCl should not be compared to salt-free samples as NaCl strongly shields the charge of the coacervate particles.

Attempts to precipitate precipitated calcium carbonate (PCC) with coacervates

Preliminary test: Decline speed

For the flocculation experiments, a suspension of precipitated calcium carbonate (PCC) in deionized water was prepared which had a concentration of 0.1% by weight. For the flocculation experiments, 20 ml of the stock solution were each filled into a sample jar. To each sample glass was then added in a coacervate / PCC ratio of 1: 2500, the coacervates summarized in Table 3, and the rate of descent of the PCC as a function of time was determined. The results are summarized in Table 8.

Sample 13 had a charge ratio PK / PA = 0.66, Sample 205 a charge ratio PK / PA = 0.66, Sample 210 a charge ratio PK / PA = 0.33 and Sample 220 a charge ratio PK / PA = 0.66. In addition, a blank sample was examined to which no coacervate was added. Table 8: Decrease rate of PCC after addition of coacervates; in each case the distance (mm) of the upper limit of the particle suspension to the surface of the liquid level in the sample glass was determined T (s) 15 30 45 60 75 90 105 120 180 240 300 2K / PA flocculation NP 0 1 1 1 1 1 1 1 2 3 3 - No 13 1 1 1 2 2 3 3 3 4 5 5 0.66 Yes 205 1 1 1 1 1 1 1 1 2 3 3 0.66 No 210 0 1 1 1 1 1 1 2 2 2.5 3 0.33 No 220 0 0 1 1 1 1 1 2 3 4 5 0.66 Yes

Samples 13 and 220 show fast visible flocculation, while samples 205 and 210 are equal in descent behavior to the blank sample (NP).

Flocculation behavior as a function of the particle charge

With the coacervates listed in Table 3, the flocculation behavior of PCC was investigated. For this purpose, 2000 μl of a 0.05% by weight suspension of PCC in deionized water were introduced into a quartz cuvette and the cuvette was inserted into the measuring chamber of a UV spectrometer. For the kinetic measurements, the absorption was measured at a wavelength of 500 nm. After the absorption of the PCC had stabilized, 4 μl of a coacervate dispersion was added at t = 1412 seconds. The dispersion had a proportion of 0.01% by weight of coacervate. This corresponds to a coacervate / PCC ratio of 1: 2500. The decrease of absorption is different for the coacervates 1 to 3 shown.

Samples 13 and 220 show a short flocculation time. In samples 205 and 210, only a slight flocculation was observed, which is also due to the fact that the flocs formed with the coacervates 205 and 210 are, above all, very small. The results of the flocculation experiments are summarized in Table 9.

For better comparability of the experiments a flocculation index F _{flakes is} recorded in Table 9. The index is calculated as follows:

In 4 the flocculation time T ₅₀ for the coacervates described in Table 3 is plotted against the charge of the respective coacervate. The flocculation time T ₅₀ is defined as the T ₅₀ time of the equivalence point subtracts the time of addition of the coacervate. In 5 For the coacervates described in Table 3, the flocculation index is plotted against the charge.

Sample 13 shows the shortest flocculation time T ₅₀ of the investigated coacervates. At a charge ratio of 0.3, the flocculation time T _{50 is} 20.6 seconds. The flocculation would therefore be completed after 41.2 seconds. The flocculation index increases slightly with increasing charge.

Sample 205, with a flocculation index of 0.3, a flocculation time T ₅₀ of 82.3 seconds, a complete flocculation after 164.6 seconds at a charge of 0.66, gives a poor flocculation behavior.

The flocculation behavior of the sample 210 with a flocculation index of 0.2, a flocculation time T ₅₀ of 130.6 seconds, which corresponds to a complete flocculation after 261.2 seconds at a load of 0.33 worse than that of the sample 205

The sample 220 shows, similar to the sample 13, a well visible flocculation behavior, but with significantly increased flocculation time. The flocculation time T ₅₀ decreases in the sample 220 with increasing charge ratio. The flocculation index shifts to higher values as the charge ratio increases, ie the flocculation behavior improves. (Flocculation index: 0.63, flocculation time T ₅₀ : 100.3 seconds, full flocculation: 200.6 seconds, charge: 0.5).

retention tests

Production of coacervates

a) Preparation coacervate (sample 013K - 1 g / l): loading range 0.1 to 0.8

Coacervates were prepared with the polyanion "FP3230 S" and the polycation "FO 4290 PG2".

To investigate whether the charge of the coacervate has any influence on the flocculation, coacervates were prepared in a charge ratio range of 0.1 to 0.8. The details of the preparation are summarized in Table 10. Table 10: Preparation of coacervates (sample 13) with different charge ratio PA / PK; Concentration 1 g / l

For the preparation of the coacervates in each case a stock solution of the polymeric anion and the polymeric cation in a concentration of 1 g / l was used. In order to achieve a complete dissolution of the polymers, the stock solutions were stirred or shaken for one day at room temperature. After the polymers had completely dissolved, it was adjusted to pH 7.0 with HCl or NaOH. To prepare the coacervates with the desired charge ratios, the stock solutions were mixed in the ratio indicated in Table 10. To ensure complete coacervate formation, incubate overnight on the shaker.

b) preparation of coacervate (sample 220-10 g / l in 0.2 M NaCl); Charge ratio range 0.2 to 0.5

Coacervates were prepared in a charge ratio range of 0.2 to 0.5. The polyanion "Satialgine S 1600" and the polycation "FO 4190 PG 1" were each dissolved in 0.2 M NaCl solution. Each batch was set at a volume of 220 ml. The details of the preparation of the coacervates are summarized in Table 11. Table 11: Preparation of coacervates of sample 220 with a charge ratio of 0.2 to 0.5 Sample 220 Monomer [g / mol] K / A cation FO4190PG1 832 4.2020202 anion Satialgine S 1600 198 relationship charge Dimensions Anion [ml] Cation [ml] 0.5 2.101010101 70.94462541 149.055375 0.4 1.680808081 82.06480784 137.935192 0.3 1.260606061 97.31903485 122.680965 0.2 0.84040404 119.5389682 100.461032 total 369.8674363 510.132564

The weighed polymers were diluted to 10 g / l with a 0.2 M NaCl solution. To completely dissolve the polymers, the samples were vigorously agitated / shaken for one day.

Only after the polymers were completely dissolved, the pH adjustment was carried out with HCl or NaOH to pH 7.0. The polymer solutions were mixed in the ratio shown in Table 11 to obtain coacervates in the desired charge ratio. The coacervation takes place overnight on the shaker.

c) preparation coacervate (sample 205-10 g / l); Charge ratio: 0.66

The coacervate of sample 205 was prepared with a charge ratio of 0.66 from the polyanion "AB 995 V" and the polycation "Alcofix". The concentration of coacervate in the sample was 10 g / l. The conditions for the preparation are summarized in Table 12. Table 12: Preparation of sample 205 sample Poly-anion Poly-cation K / A Behaves charge. Mass behaves. Anion [ml] Cation [ml] 205 FROM 995 V Alcofix 1712 0.66 1.13043 103266 116734

The weighed polymers were diluted to 10 g / l with deionized water. The samples were vigorously stirred / shaken at room temperature for one day so that the polymers completely dissolved. After adjustment of the pH with HCl or NaOH to pH 7.0, the two polymer solutions were mixed in the volume ratio indicated in Table 12 so that a coacervate with the desired charge ratio of 0.66 resulted. The coacervation took place overnight on the shaker.

d) preparation of coacervate (sample 210-10 g / l in 0.2 M NaCl); Charge ratio: 0.33

The coacervate of sample 210 was prepared at a concentration of 10 g / l with 0.2 M NaCl from the polyanion "Sokalan CP 45" and the polycation "Alcofix" at a loading ratio of 0.33. The amounts used are summarized in Table 13. Table 13: Preparation of sample 210 sample Poly-anion K / A Charge RATIOS. Mass RATIOS. Anion [ml] Cation [ml] 210 Sokalan 1788 12:33 0.5903 138.3357 81.6642

The weighed polymers were diluted to 10 g / l with a 0.2 M NaCl solution and vigorously agitated / shaken for one day to ensure complete dissolution.

The samples were then adjusted to pH 7.0 with HCl or NaOH and mixed to give the coacervates in the desired charge ratio of 0.33 in the ratios given in Table 13. Complete coacervation was on the shaker overnight.

Retention and drainage tests

The term "total retention" indicates the ratio of the amount of dry stock used to make paper, paperboard, paperboard, paper-containing composites to the amount of fabric remaining in the finished paper, paperboard, paperboard, paper-containing composites, while the term "filler retention" means the ratio of filler content of the composites for the production of paper, paperboard, paperboard, paper-containing composites, amount of dry substance used relative to the filler content of the finished paper, cardboard, cardboard, paper-containing composite material.

The term "fillers" in the context of the present invention comprises components present in the paper which are present at 25 ° C. as solids which are not paper material fibers, in particular not pulp fibers.

Determination of retention and drainage

Carrying out the retention and drainage tests

The retention and drainage experiments were carried out on a device DRF 04, the company BTG Instruments AB. Here, a pulp, the variety 910 BIO TOP 3, by the company Mondi Austria was used.

The following stirring profiles or settings were selected on the device:

For retention:

• Pulp suspension: 0.96% by weight of pulp, based on the total weight of the pulp suspension.
• Polymer: Percol ^® 178 (Ciba AG), 0.1 wt .-% of polymer, based on the total weight of the polymer solution; freshly prepared solution.
• Coacervate: 0.1% by weight of coacervate, corresponding to 50 g / t of pulp
• Stirring profile: Stir and add polymer at 750 rpm (revolutions per minute) for 3 s (seconds), then stir at 1400 rpm for 15 s, then stir and add bentonite and coacervate for 3 s at 750 rpm and continue at 1200 rpm for 7 s Stirring, then at 400 rpm for 1 s. Detection of retention after pouring onto a sieve 24 mesh.

The device calculates the total and filler retention directly.

For drainage:

• Pulp suspension: 0.95% by weight of pulp, based on the total weight of the pulp suspension.
• Polymer: Percol ^® 178 (Ciba ^® AG), 0.1 wt .-% of polymer, based on the total weight of polymer solution corresponding to 100 g per tonne of pulp; freshly prepared solution.
• Coacervate: 0.1% by weight of coacervate, corresponding to 50 g / t of pulp
• Stirring profile: stirring for 3 s at 750 rpm and polymer addition, then stirring at 1000 rpm for 15 s, then adding bentonite and coacervate for 3 s at 750 rpm and stirring at 1200 rpm for 7 s, then collecting drainage by pouring onto a net 60 mesh.

The device calculates directly the drainage after pre-set time, d. H. after 5 s, 10 s and 30 s.

Used materials

cellulose

It was used a wood-free pulp (Mondi, Austria).

bentonite

As a bentonite and soda activated bentonite (Opazil ^® AOG, Süd-Chemie AG) was used.

Cationic polymers

Cationically charged polyacrylamides (PAM) from ^Ciba® AG were used. The polyacrylamides from the Percol family were particularly Percol ^® 178, used.

coacervate

The coacervate of sample 13 was used at a charge ratio of 0.2.

As a comparison, retention and drainage were also determined analogously for the Telioform ^® system as well as for a two-component system. For the Telioform ^® system, 100 g / t pulp Telioform ^{® was} added. The two-component system used only the cationic polymer and bentonite.

The results of the retention experiments are shown in Table 14, the results of the drainage experiments are summarized in Table 15. Table 14: Results of the retention experiments (pulp: 0.96% by weight of cationic polymer: 0.1% by weight) Ex. bentonite TELIOFORM coacervate Retention (%) (Kg / t) (Wt .-%) (Wt .-%) Total Fill. 1 0 0 0 77.5 37.7 2 1 0 0 83.0 54.2 3 1.5 0 0 84.6 58.9 4 2 0 0 85.2 60.8 5 1 0.1 0 84.3 58.0 6 1.5 0.1 0 85.8 62.4 7 2 0.1 0 87.4 66.9 8th 1 0 0.1 85.6 61.5 9 1.5 0 0.1 87.0 66.2 10 2 0 0.1 86.3 64.0 Table 15: Results of the drainage tests (pulp: 0.95% by weight, cationic polymer: 0.1% by weight) Ex. bentonite TELIOFORM coacervate Drainage (g) (Kg / t) (Wt .-%) (Wt .-%) 5 s 10 s 30 s 11 0 0 0 164 240 405 12 1 0 0 219 310 506 13 1.5 0 0 223 323 522 14 2 0 0 238 340 548 15 1 0.1 0 242 344 560 16 1.5 0.1 0 250 355 573 17 2 0.1 0 274 395 633 18 1 0 0.1 221 318 513 19 1.5 0 0.1 244 355 559 20 2 0 0.1 276 382 610

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0235893 B2 [0011]
• WO 02/33171 A1 [0013]

Cited non-patent literature

• DIN 66131 [0026]
• DIN 66131 [0096]
• EP Barrett, LG Joyner, PP Hienda, J. Am. Chem. Soc. 73 (1951) 373 [0096]

Claims (17)

A process for the preparation of filled paper or paperboard, wherein an aqueous fiber suspension is prepared containing fibers and at least one filler, and the fiber suspension is flocculated with a flocculation system comprising as components at least one inorganic microcomponent and a coacervate, which consists of at least one cationic Polymer and an anionic polymer is formed, and the flocculated fiber suspension is processed into a filled paper or a filled paperboard. The method of claim 1, wherein the coacervate has an excess charge. A process according to claim 1 or 2, wherein the anionic and cationic polymers are contained in the coacervate in a charge ratio ranging from 0.1 to 0.95. Method according to one of the preceding claims, wherein first an aqueous dispersion of the coacervate is prepared and the aqueous dispersion of the coacervate is then added to the aqueous fiber suspension. The method of claim 4, wherein the coacervate dispersion has a coacervate content in the range of 0.1 to 15% by weight. A method according to any one of claims 4 or 5, wherein the coacervate dispersion contains an electrolyte. Method according to one of the preceding claims, wherein at least one of the at least one cationic and at least anionic polymers contained in the coacervate has a linear structure. The method of any one of the preceding claims, wherein the coacervate-forming at least one cationic polymer and the at least one anionic polymer has a molecular weight greater than 50,000 g / mol. A process according to any one of the preceding claims, wherein the cationic polymer comprises cationic monomer units and the proportion of the cationic monomer units in the entirety of the cationic polymer forming monomer units is at least 1 mol%. Method according to one of the preceding claims, wherein the cationic polymer is selected from the group of polyacrylamides, polyethyleneimines, polyvinylamines, polyethylene glycols, poly-DADMAC, as well as native polymers, in particular cationic starch and chitosan. A process according to any one of the preceding claims, wherein the anionic polymer comprises anionic monomer units and the proportion of the anionic monomer units of the entirety of the anionic polymer forming monomer units is at least 1 mol%. Method according to one of the preceding claims, wherein the anionic polymer is selected from the group of polyacrylates, polyacrylamides, as well as copolymers of acrylates and acrylamides, anionic starch, cellulose derivatives, such as carboxymethyl, -ethyl, -propylcellulose, cellulose ethers, alginates and carrageenans, Polysulfonates, polyphosphates. A method according to any one of the preceding claims, wherein the filler is selected from calcium carbonate, titanium dioxide, talc, kaolin, diatomaceous earth, magnesium carbonate, barium sulfate, zinc sulfide and calcium silicates. Method according to one of the preceding claims, wherein the flocculation system contains at least one further flocculation component selected from at least one further anionic polymer and at least one further cationic polymer. Method according to one of the preceding claims, wherein the addition of the components of the flocculation system is carried out sequentially. The method of claim 15, wherein the fiber suspension is sheared after addition of at least one component of the flocculation system. Method according to one of claims 15 or 16, wherein the coacervate is added to the fiber suspension as the last component of the flocculation system and the fiber suspension is no longer sheared after the addition of the coacervate.

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