DE102004023864A1 - Production of surface-modified inorganic filler or pigment, used in dispersion paint, adhesive, coating or paper coating mass, involves milling with polymer dispersion and usual milling aid and/or dispersant - Google Patents

Abstract

Production of surface-modified inorganic filler or pigment of desired particle size comprises milling a filler/pigment (I) slurry to the desired particle size by applying pressure and shear, with addition of polymer dispersion (II), and also bringing (I) into contact with 0.1-2.0 wt.% known milling aid (III) and/or dispersant (active substance) (IV) with respect to (I). An independent claim is also included for surface-modified inorganic fillers and/or pigments produced by this process.

Description

object The invention is a process for producing surface-modified inorganic fillers and pigments of defined grain size, the so obtained fillers and pigments and their use.

In Many areas of engineering use inorganic pigments or fillers bound with binders in the form of polymer dispersions, for example in the production of emulsion paints, adhesives or paper.

The EP 0 515 928 B1 relates to surface-modified platelet-shaped pigments with improved stir-up behavior and their method of preparation and use. The platelet-shaped pigments, for example platelet-shaped metals, metal oxides, mica pigments and other platelet-shaped substrates are coated in a mixing vessel with stirring with a polyacrylate or polymethacrylate or their water-soluble salts and optionally a solvent or solvent mixture.

For example in the production of paper is a large amount of fillers used. Almost all papers are mixed with fillers that are extra Printing and writing paper a uniform formation, better switch, white and give grip.

Natural printing papers (uncoated papers) contain up to 35% by weight, coated Papers 25 wt .-% to 50 wt .-% fillers. The amount of filler hangs a lot from the intended use of the paper. Own heavily weighted papers lower strengths and poorer sizing.

Of the filler in the pulp is usually between 5 and 35% by weight and consists of primary pigments or recirculated Coating pigments obtained from residual coatings or coated rejects can come. In addition to the white of the filler, the for white-tinted papers importantly, the grain size plays an essential Role, as it is the filler yield strong and the physical properties of the paper, in particular the porosity affected. The amount of filler remaining in the paper is between 20 and 80% by weight the amount of fiber suspension added. The yield depends both of the filler type as also of material composition, the freeness, the fixation of the filler particles by resin and aluminum sulfate, paper weight, paper machine speed, the type of dehydration and the fineness of the sieve.

Corresponding Consumption has the following products as filler and coating pigment today the greater importance: Kaolin, calcium carbonate, artificial Aluminum silicates and hydrates, titanium dioxide, satin white, talc and calcium silicate.

The WO 98/01621 describes a process for recycling fillers and coating pigments of paper, board and cardboard manufacture the residual water sludge the sprinkling wastewater, Deinking plants, in-house sewage treatment plants or separation devices and the use of a resulting pigment slurry for the production a coating for the paper industry or for the mass use in papermaking. An essential element The invention consists in a process for the recycling of fillers and coating pigments of paper, board and cardboard manufacture the residual water sludge the sprinkling wastewater, Deinking plants, in-house sewage treatment plants or separation devices, which is characterized by containing the filler and coating pigment residual water sludges mixing and then the grinding to a pigment slurry with fresh pigment or fresh filler as a powder, freshpigmenthaltige and / or Frischfüllstoffhaltige Slurry feeds.

The The object of the present invention is to improve the Contact of inorganic fillers and pigments and binders (binders) in the form of polymer dispersions and thus a reduction in the necessary amount of binders or an improved binding of the fillers or the pigments with each other and on the substrate, for the production of filler or pigment slurries, especially in the paper industry and other applications, like the paint industry or the adhesives industry.

According to the invention was found that inorganic pigments of defined particle size, whose surface while the grinding with binders, hereinafter as polymer dispersions referred to in many areas of technology, for example in the Paper industry and the paint industry or the adhesives industry, can be used with advantage.

Accordingly There is a first embodiment of the present invention in a process for the preparation of surface-modified inorganic fillers and pigments of defined grain size thereby characterized in that filler or pigment slurries of inorganic fillers or pigments under the action of shear forces, in particular Addition of polymer dispersions to the desired grain size milled.

It It has been found that polymer dispersions, which usually have an adhesive effect should be suitable, inorganic fillers and pigments in one To provide form opposite the prior art known fillers and pigments same Particle size distribution an elevated one binding capacity when adding binders with surfaces of inorganic fillers and pigments during the grinding of the fillers and pigments to the desired Grain size in contact brings. The binders can thereby come from recycled materials, such as residual water sludge or else added directly.

Surprisingly it was found that the polymer particles did not stick together or agglomerating the filler particles and lead pigment particles, but apparently a fine film on the surface of the fillers or pigments that form a much better adhesion to each other and to the substrate, for example fibers in the paper industry.

Especially preferred filler or pigment for modification in the sense of the present invention is calcium carbonate, especially natural and / or precipitated calcium carbonate.

Next Calcium carbonate can also used in the art known fillers and pigments such as kaolin, artificial and / or natural aluminum silicates and - oxide hydrates, Titanium Dioxide, Satin White, Dolomite, mica, metal, especially aluminum flakes, bentonite, Rutile, magnesium hydroxide, gypsum, phyllosilicates, talc, calcium silicate as well as other stones and earths.

Especially For the purposes of the present invention, it is preferred that those defined above fillers and pigments in an amount of 10 to 90% by weight, especially 30% to 70 wt .-%, based on the slurry, in particular to use water.

At the Applying the fillers or pigments, for example as a component of coating color in papermaking, usually migrates a high proportion of the binder in the paper surface. A large Part of the binder beats into the raw paper before it comes to filming. The top one Coating depleted of binders and it comes to the so-called Plucking. However, if the polymer binder on the filler or the pigment is ground, migration of the binder occurs not or only to a small extent; this means the offset strength (resistance to plucking) is higher because no (or little) binder is lost by knocking off. in the The prior art, however, the loss of binder by a increased Binder content can be compensated in the coating color.

polymer dispersions For the purposes of the present invention, the resin solids include in itself and their dispersions (latices) of finely divided natural and or synthetic polymers, in particular in a particle size of 0.05 up to 6 μm. Usually are these in the form of aqueous, less common non-aqueous Dispersants before. Included are thus dispersions of Polymers such as natural (latex rubber) and synthetic rubber (synthetic latex), as well as synthetic resins (synthetic resin dispersions) and plastics (Plastic dispersions) such as polymers, polycondensates and Polyadditonsverbindungen, in particular based on polyurethane, Styrene / butadiene, styrene / acrylic acid or esters, styrene / butadiene / acrylic acid or esters and vinyl acetate / acrylic acid or ester and acrylonitrile-containing suspensions.

Under the product Basonal ^®, Acronal ^® and Styronal® ^® corresponding polymer dispersions are commercially available as binders for the dispersion paint industry and also for paper and board on the market. In the prior art, these polymer dispersions are incorporated by stirring into the customarily neutral to alkaline filler or pigment slurries without further shearing, without a change in the particle size of the filler particles or pigment particles occurring here. For the purposes of the present invention, however, they are used directly with the inorganic fillers and pigments brought into contact by the action of pressure and shear forces. Of course, the same applies to the production of filler or pigment slurries, for example in the production of adhesives, in which no water is added separately. Under the influence of compressive and shear forces during milling surface-modified inorganic fillers and pigments are obtained, which have an improved binding effect compared to the prior art. For the purposes of the present invention, it is particularly preferred to wet-mill the inorganic fillers or pigments in the presence of the polymer dispersions to the desired particle size. Thus, for white fillers or pigments, it is possible to produce a large variation in the whiteness and size distribution of the fillers or pigments, which variation can be controlled, in particular, by the nature and duration of the milling.

The Amount of polymer dispersions containing the inorganic fillers or pigments is brought into contact, is of a certain Importance. Thus, it is particularly preferred for the purposes of the present invention, the inorganic fillers or pigments in an amount of 0.1 to 50, especially 5 to 15 Wt .-% polymer dispersion (solids), based on the amount of To bring pigment into contact. The polymer dispersions are usually in water or non-aqueous Form having a solids content of 40 to 60 wt .-%, in particular 50 wt .-% before.

Next The polymer dispersions are within the meaning of the present invention still possible that one the inorganic fillers or pigments with dispersants or grinding aids known per se, in particular Contact polyacrylates.

Such polyacrylates are, for example, in the aforementioned EP 0 515 928 B1 to which reference is made in full.

in the For the purposes of the present invention, it is particularly preferred that fillers or pigments with the above-mentioned dispersant active substance in in an amount of 0.1 to 2.0, in particular 0.2 to 0.4 wt .-%, based to contact the solid substance.

In the residual water sludge the sprinkling wastewater paper and deinking plants, in-plant facilities or Separators are the fillers and coating pigments often in agglomerated form and with less whiteness, which is a direct reuse in the processing of raw materials, especially in the paper line, limits or even impossible power.

With Help the present invention of the method described above becomes a defined, concentrated pigment slurry or filler slurry also obtained using residual water sludge, for example in the paper, cardboard and paperboard manufacturing or paint and adhesives industries can be used.

In the papermaking industry it is common the fillers and spread pigments both as a powder or in the form of a concentrated one Slurry having 50 to 80 wt .-% solids, use. These fillers and Pigments are becoming common from the manufacturers with the desired white and particle size distribution to disposal posed. An essential element of the present invention is now in the use of inorganic fillers and pigments in one Type "basic grain", preferably as Solid or as a highly concentrated slurry, for example having a solids content of 70% by weight to 85% by weight or more, for example with an average grain diameter of 50% <1 μm to 50 % <15 μm, in particular 50% <3 μm to 50 % <8 μm and grinding in the presence of the polymer dispersion, especially in aqueous Phase to the desired Grain size. Consequently can for example, in the paper industry by mixing and then the Milling of fresh pigment or fresh filler as a powder, freshpigmenthaltige and / or Frischfüllstoffhaltige Slurry to the desired white and fineness and then as a filler or coating pigment be used. The mineral fillers and pigments mentioned are usually milled in wet or dry process to the desired grain size. When wet grinding naturally a proportion of water is required. Part or all of the necessary water for grinding The inorganic pigments can be replaced by the residual water sludge can. Usually in the residual water sludges present agglomerates of the fillers or disturb pigments This is not or little, as these in the course of the milling process to the desired Particle size crushed become.

The pigment and filler particles of the residual water sludge, which are intended for use as a filler or pigment, act as grinding aids and dispersing aids for the destruction of the agglomerates in the milling process. At the same time the residual water sludge including the loaded particles acts as Dispersing aids and grinding aids for the added fillers and pigments in the milling process, so that the usual amounts of binders, dispersants and grinding aids can be reduced according to the invention.

Accordingly it is particularly according to the invention preferably, the residual water sludge having a solids concentration from 0.02% by weight to 60% by weight, in particular from 1% by weight to 30% by weight for mixing and subsequent Milling with polymer dispersion and fresh pigment or fresh filler as a powder, freshpigmenthaltige and / or Frischfüllstoffhaltige Adjust slurry. If the concentration is too low, the Recycling process uneconomical.

In the residual water sludge The paper industry can reduce the ratio of fillers and / or pigments to fibers in a big one Bandwidth vary. It is particularly preferred for the purposes of the present invention, residual water sludges with an optionally enriched concentration of fillers and / or Use pigments in the range from 1% to 80% by weight, in particular from 20% by weight to 60% by weight, based on the solids content lies. Thus, the fiber content on the one hand or the filler and / or On the other hand, for example, from 2 to 98% by weight or 98 to 2 wt .-% vary. Also in the paper industry are of course fiber-free residual water sludges used according to the invention.

exemplary Here are the preferred compositions of various residual water or sewage sludge explained. Preferably, the wastewater from the production comprises 0.5 to 5 wt .-%, in particular 2.5 wt .-% loss of material at a specific fresh water requirement from 10 to 100 l / kg, in particular 20 l / kg. The concentration of residual water sludges is preferably 0.02 to 5.0, in particular 1.5 wt .-%. Especially preferred For the purposes of the invention, here is a ratio of fiber content to filler and / or Pigment content of 20 to 80 wt .-% or 80 to 20 wt .-%, in particular Fibers to pigment in proportion 40 to 60 wt .-% of a wastewater from the paper production.

preferably, is a slurry having a solids content of 10 to 95 wt .-%, in particular 40 to 80 wt .-% ground.

This allows a flexible and fast response to quality and quality Production requirements, for example of different paper raw materials for the Pulp, the fillers or pigments or slurries for the pre-coat, top coat and single-stroke or pigmentation alone, as well as mixing with other fillers or pigments.

in the For the purposes of the present invention, known additives can be used such as wetting agents, stabilizers, grinding aids and dispersing aids while the mixing and / or the grinding of the inorganic fillers and pigments are used.

The Especially, pigment slurries obtainable by the present invention can be used advantageous in the paper industry, in particular for the production a coating color for be used in the paper stock or in the pulp. Especially preferred is the use for preparing a coating pigment slurry for offset paper. About that In addition, the slurries according to the invention are also suitable for the production a coating for lightweight, coated papers, especially at high Order speed and for the production of roll offset papers, in particular for the production of lightweight, coated Rotary offset papers, the painting of cardboard and special paper, such as labels, wallpapers, Silicone base paper, carbonless papers, packaging papers, as well as the admixture with gravure papers. In this sense are the inventively available Coating pigment slurries, particularly applicable in sheetfed offset, in particular for the sheetfed single stroke, Sheetfed double stroke: sheetfed offset and sheetfed cover slip; - in web offset, especially for the LWC web offset single stroke, web offset double stroke: web offset pre-stroke and web offset top coat; - in the Gravure, especially for the LWC gravure single stroke, gravure double stroke: gravure priming and gravure top coat; - in the Cardboard, especially for the carton double line: cardboard precoat and cardboard top coat as well Flexo printing and for Special papers, especially for Labels and flexible packaging. The fillers of the invention and Pigments can also in paper for digital printing methods are used advantageously.

The Procedure offers the possibility the inventively prepared Pigment Slurries without loss of quality in the used to produce raw papers, lines and in particular the final qualities.

The present invention can be used in particular for the production of adhesives. As is well known, adhesives are non-metallic substances which combine adherends through adhesion (surface adhesion) and internal strength (cohesion). Adhesive is a generic term and includes other common terms for types of adhesives chosen according to physical, chemical or processing aspects, such as size, size, dispersion, solvent, reaction, contact adhesives. The names of the adhesives often include additives for the identification of basic materials (for example starch paste, synthetic resin glue, skin glue), processing conditions (for example cold glue, heat-seal or hot-melt adhesive, assembly glue), intended use (for example paper glue, wood glue, metal glue, wallpaper glue, rubber glue). Adhesive) and delivery form (for example, liquid adhesive, glue solution, glue powder, tablet paste, glue jelly, putty, adhesive tape, adhesive foil).

adhesives are predominantly based to be organic compounds, but also inorganic adhesives used.

DIN 16 920 divides adhesive types into physically setting (glues, Pastes, solvents, Dispersion, plastisol and hot melt adhesives) and chemically setting (For example, cyanoacrylate adhesives). The physically setting adhesives can be solvent-free (hot-melt adhesives) or solvent-containing be. They bind by change the state of matter (liquid ⇒ solid) or by evaporation of the solvents before or during of the bonding process and are generally one-component.

The chemically setting, one- or multi-component reaction adhesives can based on all polymerization reactions: two-component systems from epoxy resins and acid anhydrides, or polyamines react according to polyaddition, cyanoacrylates or methacrylates after polymerization and systems on aminoplastics or phenolic based on polycondensation mechanisms.

The Range of usable as adhesive raw materials monomers or Polymer is widely variable and makes bonding of almost all materials possible. The problem is often the bonding of plastics.

dominant The aim of ongoing adhesive developments is the (from ecological and economic point of view mandatory) conversion of organic solvents containing on Solvent-free or water as a solvent containing systems.

Also for the production of paints and varnishes are the fillers of the invention or pigments suitable. The fillers are particularly preferably used or pigments for the production of emulsion paints and disperse dyes. The latter means a group of sparingly soluble in water synthetic dyes (in most cases azo dyes or anthraquinone derivatives, also naphtol AS dyes), which are very finely ground together with dispersants for dyeing and Printing of acetate, polyester, polyamide, polyacrylonitrile, PVC and polyurethane fibers are used. During dyeing, those in the dyebath penetrate molecularly dissolved Dye components by diffusion into the fiber, form there a solid solution and this gives real colorations. A modern variant is the so-called transfer printing, in which Disperse dyes of paper thermally transferred to fabrics become.

So Is it possible, relative coarse inorganic fillers or to add pigments to a fine grinding. The user of the fillers according to the invention and pigments is not at given particle sizes of Tied to suppliers of raw materials. In many areas of the state Technically it is custom finished Filler or pigment slurries the raw material provider with the number of weight percent of particles smaller than 2 μm to characterize, for example as quality, fineness or type 95, 90, 75, 60, 50 etc.

In Many fields of technology plays in the use of fillers or pigments the particle size distribution a special role. It is within the meaning of the present invention particularly preferred, fillers or to use pigments having a particle size distribution of 10 to 99 Wt .-% of particles <10 .mu.m, in particular 10 to 95 wt .-% of particles <1 micron, respectively based on the equivalent diameter exhibit.

• a) 95 bis 100 Gew.-% an Teilchen < 20 μm und/oder
• b) 50 bis 100 Gew.-% an Teilchen < 2 μm, insbesondere 50 bis 95 Gew.-% an Teilchen < 2 μm und/oder
• c) 27 bis 99 Gew.-% an Teilchen < 1 μm, insbesondere 27 bis 75 Gew.-% an Teilchen < 1 μm und/oder
• d) 0,1 bis 55 Gew.-% an Teilchen < 0,2 μm, insbesondere 0,1 bis 35 Gew.-% an Teilchen < 0,2 μm, jeweils bezogen auf den Äquivalentdurchmesser.

For the purposes of the present invention, particular preference is given to fillers or pigments having a particle size distribution of

• a) 95 to 100 wt .-% of particles <20 microns and / or
• b) 50 to 100 wt .-% of particles <2 microns, in particular 50 to 95 wt .-% of particles <2 microns and / or
• c) 27 to 99 wt .-% of particles <1 micron, in particular 27 to 75 wt .-% of particles <1 micron and / or
• d) 0.1 to 55 wt .-% of particles <0.2 .mu.m, in particular 0.1 to 35 wt .-% of particles <0.2 .mu.m, in each case based on the equivalent diameter.

following are preferred fields of application of the method according to the invention and the resulting fillers or pigments discussed.

Farben:

The classic recipe of an interior emulsion contains in the Usually a share of about 10% of a polymer dispersion based Styrene acrylate. A classic facade color recipe has in the Usually a proportion of 18 to 25% of a polymer dispersion.

According to the invention was found using a polymer dispersion coated Filler slurry the proportion of the total dispersion or the resin content of the final formulation with the same strength of the recipe as before, be lowered can, or that at the same resin content in the formulations as before the Strength increases significantly. In the present case, therefore, a Standard formula so equipped, that 50% of the binder contained in the recipe exchanged become. Due to the need for a coated calcium carbonate slurry as a basis for the experiments is taken is then analogous to the solids content of the Claciumcarbonats used in the standard formulation and in the comparison recipe modified so that the previously dry in the dispersion introduced fillers adequate used by the same amount of slurry calculated on solids become. This has the consequence that there are two identical recipes, with adequate equal amounts of binders and equal amounts of inorganic Fillers. In the latter case, however, a share was as described above, from the previous standard formulation share by the newly designed coated according to the invention Exchanged carbonate slurry. This proved that the strength adequate of the paint increases by here the washability according to DIN was taken as the basis. The using the fillers of the invention or pigments produced colors had a significantly improved resistance on.

In Another case was the resin content in the recipe compared to the Standard recipe lowered by 20% by weight. The remaining 80% by weight of the recipe contained resins were replaced by, in absolute terms, these remaining 80% by weight each half by adding normal standard dispersion and coated in the other half according to the invention Carbonate slurry according to the new Procedures were used. Again, the washability was again measured in comparison to the standard. The using the fillers of the invention or pigments produced colors had a significantly improved resistance on.

adhesives industry

A Adhesive formulation contains classically for a typical floor adhesive for the adhesion of textile or other soils accounted for 35% of a terpolymeric dispersion having a resin content of 50%.

in the In the present case, part of the binder became part of it exchanged on the basis of the present invention, so that the total amount the resin in the formulation remained the same as before, as did the filler content in the recipe opposite Standard stayed the same.

demonstrated It should be that the strength compared to standard clear has improved.

The so prepared formulations were used by bonding with a predetermined standard carpet floor on a solid Underground was made and afterwards compared, which force was necessary to delaminate the thus glued together layers. Those produced using the fillers and pigments of the invention Adhesives had significantly higher Delaminierkräfte on.

paper industry

In the paper industry coating colors are usually used for the surface coating, which contain about 10% by weight of a polymer dispersion (solid). In the present case, the standard coating color was based on calcium carbonate with 10% by weight of polymer dispersion (solid). As an alternative, the same formulation was prepared with equal amounts of carbonate and binder, however, a part of the previous formulation was modified by both binder and calcium carbonate was adequately replaced by coated according to the invention Calciumcarbonatslurry, wherein the same polymer dispersion was used for the coating, which so far only was added as a component in the recipe. Compared Then then the Rupffestigkeit of the coating, wherein in both cases before the above recipe a base paper with about 14 to 15 g / m ^{2 was} coated, on the one hand with standard, on the other hand with the alternative. The pick resistance provides information about which coating film is better connected to the raw paper. The pick resistance of the papers using the fillers and pigments according to the invention was markedly improved over standard fillers and pigments.

With These three examples could then be proven in terms of application technology be that a coat in liquid Phase of the inorganic filler a significant improvement in the strength values of the coating results opposite the traditional application by dispersions and inorganic Fillers only be mixed.

A particularly preferred application of the present invention the use of residual water sludge, especially in the paper industry.

In The paper manufacturing losses of coating colors or coating components occur between 4% by weight and 12% by weight of the material used lie.

• • an den Streichaggregaten z.B. durch Sortenwechsel, Abrisse, Abstellen und Wiederanfahren der Anlage,
• • in der Streichfarbenaufbereitung, z.B. bei Fehlchargen, Filtrieren,
• • im Rohstofflager, beim Entladen von Tankzügen, Befüllen und Entleeren von Behältern.

These residual coating colors or rejects arise mainly at position A of FIG.

• • on the coating units, eg by changing grades, breaks, parking and restarting the system,
• • in coating color preparation, eg in faulty batches, filtration,
• • in the raw materials warehouse, when unloading tank trucks, filling and emptying containers.

Such disorders are associated with cleaning work, so that the rejuvenating waters in usually only small amounts of solids by 1 - have 2% by weight. The rejects are mostly - as well in the present case example - without Separation in a "waste collection container" collected at Pos. B.

• a) Der Weg zur Deponie In den meisten Fällen – wie auch in dem hier beschriebenen Anwendungsfall – werden die Rejekte z.B. mittels Zentrifuge (Pos. C) oder Sedimentationsprozess (Pos. D) geflockt, entwässert und auf maximalen Feststoffgehalt (> 55%) gebracht und in dieser Form auf der Deponie „entsorgt". Hochwertige Einsatzstoffe wie Pigmente und Bindemittel gehen dem Produktionsprozess verloren.
• b) Rückführung in den Papierstreichprozess mit Hilfe der vorliegenden Erfindung, bei gleichzeitigem Qualitätszugewinn für das Calciumcarbonatpigment. Dazu wird die vorliegende Erfindung in den Produktionskreislauf der Papierfabrik integriert.

At this point, the paper mill can take different paths, eg

• a) The way to the landfill In most cases - as also in the application described here - the rejects are flocculated eg by means of centrifuge (item C) or sedimentation process (item D), dehydrated and brought to maximum solids content (> 55%) and disposed of in this form at the landfill High-quality raw materials such as pigments and binders are lost to the production process.
• b) recycling in the paper coating process by means of the present invention, with simultaneous quality gain for the calcium carbonate pigment. For this purpose, the present invention is integrated into the production cycle of the paper mill.

First the rejects are flocculated with the addition of cationic products. Pigments and coagulated binder are separated from the water. For this purpose, sedimentation facilities (Item D) or decanter (item E). Also the centrate of the centrifuge Pos. C can be used; the resulting clear water is called Production water is used or goes to the sewage treatment plant without polluting it.

Pos. F

Pufferbehälter für geflocktes und aufkonzentriertes Rejekt,

Pos. G

Silo für CaCO₃-Pulverware

Pos. H

Mischer für Mischungen von trockenem CaCO₃ und Rejekt

Pos. I

Vorratsbehälter für CaCO₃ Slurry

Pos. K

2-stufige Kugelmühle

ggf. Pos. L

ggf. Zwischenbehälter für fertig gemahlene CaCO₃ Slurry

The positions C and D are usually parts of the paper mill, position E is part of the present invention. In the application described here, the concentrated reject from the factory's own sedimentation hopper enters the grinding plant. This consists of the following elements:

Pos. F

Buffer tank for flocculated and concentrated rejects,

Pos. G

Silo for CaCO ₃ powdered goods

Pos. H

Mixer for mixtures of dry CaCO ₃ and reject

Pos. I

Reservoir for CaCO ₃ slurry

Pos. K

2-stage ball mill

if necessary pos. L

if necessary intermediate container for ready ground CaCO ₃ slurry

• • Aufkonzentriertes Rejekt wird im Pufferbehälter F gesammelt. Fällt kein Rejekt an, wird der Behälter mit Wasser beschickt.
• • Im Mischer H wird Rejekt und gegebenenfalls Dispergiermittel vorgelegt und dann das CaCO₃-Pulver aus dem Silo G bei 75 bis 80 Gew-% Feststoff dispergiert.
• • Im Vorratsbehälter I wird die Slurry zwischengelagert und von da aus
• • die Kugelmühle K kontinuierlich beschickt. In der Mühle wird die Slurry unter der Zugabe von Mahlhilfsmittel auf die gewünschte Feinteiligkeit vermahlen. Diese Calciumcarbonat-Slurry wird im
• • Behälter L zwischengelagert und dieselbe Slurry anschließend, nach Kontrolle von Teilchengröße, Feststoff, Viskosität und pH- Wert mit Polymerdispersion in der Streichküche versetzt und die so geschaffene Streichfarbe in den
• • Vorratsbehälter M der Streichanlage transportiert. Bei kontinuierlichem Betrieb kann in dem erfindungsgemäßen Verfahren auch auf die Behälter F und I verzichtet werden.

As in the case of application, this works as follows:

• • Concentrated reject is collected in buffer tank F. If no reject occurs, the container is charged with water.
• • In the mixer H reject and optionally dispersing agent is introduced and then dispersed the CaCO ₃ powder from the silo G at 75 to 80% by weight of solids.
• • In the storage container I, the slurry is stored intermediately and from there
• • The ball mill K is fed continuously. In the mill, the slurry is ground to the desired fineness with the addition of grinding aid. This calcium carbonate slurry is used in the
• • Store container L and then add the same slurry, after checking particle size, solids, viscosity and pH, with polymer dispersion in the coating kitchen and apply the coating color to the coating
• • Transport reservoir M of the coater. In continuous operation, the container F and I can be dispensed with in the process according to the invention.

at the reuse of the rejects according to the present invention can theoretically, the pigments alone are separated and recycled. The inventive method but also sees a return of the Binder ago, because the grinding of the pigment with the binder is crucial for the quality of the manufactured Carbonatpigmentes. It is irrelevant whether the binder in its original Form as finely divided polymer dispersion or in flocculated, i. coagulated state is present as a pebble, because as a coagulum the binder has its potential effect. When grinding is due to the mechanical rubbing between the balls of the Binder - whether as a single particle or agglomerate - rubbed on the pigment particles and filmed by the high temperature. The filler or pigment particles are therefore covered with filmed binder.

This Binder content is already firmly anchored and can not more in the absorbent Turn away the substrate (raw paper or cardboard). The waybill means loss of binder or depletion of the stroke on Binder, and with it are e.g. Scratch resistance and print gloss lower. The knocking off can also be irregular, if different more absorbent Zones in the base paper are present. This then leads to a spotty Printed image (Mottle).

Becomes in contrast, as in the method according to the invention a filler or pigment applied to the paper / cardboard already is coated with binder, there is no migration of this binder. The "yield" of the binder is higher; you get denser strokes, higher Rupffestigkeit and better printing gloss with less binder use. With homogeneous distribution of the coating pigment is also the binder equally distributed, resulting in a uniform ink absorption leads and counteracts the mottle. This is through trials and experiences with different binders both in the form of stabilized Polymer dispersion as well as in the form of destabilized binder, this means Binder agglomerates proved.

embodiments

• • Papierfabrik mit einer Papiermaschine und einer Jahresproduktion von 100.000 t gestrichenem Papier.
• • Papiermaschine mit on-line Streichaggregaten versehen für Vorstrich und Deckstrich.
• • Gesamtpigmentverbrauch 40.000 t, davon 20.000 t CaCo₃ einer 60-er Feinheitsqualität für den Vorstrich.
• • Rejektanfall 3.200 t/Jahr
• • Kapazität der Anlage zur Durchführung des erfindungsgemäßen Verfahrens 24 t/Tag mit CaCO₃ (60-er Feinheit)
• • Ziel: Vermahlung von 20 t Frischpigment mit 1 t Rejekt bei einem Feststoffgehalt von 75 Gew.-%.

In a practical experiment the following investigations could be confirmed

• • Paper mill with a paper machine and an annual production of 100,000 t of coated paper.
• • Paper machine equipped with on-line coating units for pre-coat and top coat.
• • Total pigment consumption 40,000 t, of which 20,000 t CaCo _{3 has} a 60-fineness grade for the precoat.
• • Reject attack 3,200 t / year
• • Capacity of the plant for carrying out the process according to the invention 24 t / day with CaCO ₃ (60 fineness )
• • Aim: Milling of 20 t fresh pigment with 1 t reject at a solids content of 75% by weight.

The Integration of the grinding plant begins with the collection of already flocculated and about 40 wt .-% thickened rejects in the buffer tank F, which already contain the polymer dispersion.

In the mixer N, the reject and dispersant were introduced and entered from the silo G dry CaCO ₃ (30-quality), up to 75% by weight of solid can be achieved. The resulting suspension was pumped into the reservoir I and there 1.8 wt .-% of a commercial grinding aid (polyacrylate), based on pigment added.

From the reservoir I, the 2-stage ball mills K were now fed continuously. The CaCO ₃ 30-er quality was ground to CaCO ₃ 60-er quality. For grinding, 85 kW had to be used per t. The 60% grade slurry thus prepared was stored in the intermediate container L until particle size, viscosity, solids content and pH were detected and then pumped into the pre-coat pigment reservoir M of the coating kitchen. Then also this precoating pigment with about 16 wt .-% (commercial product) was a commercially available polymer dispersion (Acronal ^®) is mixed, so that to obtain a precoating color.

In the case of application described here, the precoat paint set itself apart during the trial 60% by weight of standard 60% fineness plus 40% by weight of AlphaCarb ° 60 fineness together, this proportion of 40% by weight consisting of 15% by weight of reject and 25% by weight of CaCO _3. he fineness was such that the proportion of the reject on the precoat paint was about 7% by weight reject. At a brushing speed of 820 m / min. were applied to the film press in the precursor 10 - 11 g / m ² / side. The running behavior of the coating color on the film press was perfect and the top coat was applied streak-free.

The thus painted test preparation was coated with standard Compared to paper.

Result:

• • einen höheren Rupfwiderstand bei Offsettest von Note 1 gegenüber Note 2,
• • einen höheren Druckfarbenglanz von 82 gegenüber 75,
• • ein langsameres Wegschlagverhalten der Druckfarbe um ca. 15 sec. nach dem Prüfbau Wegschlagtest,
• • eine bessere Druckgleichmäßigkeit (visuell beurteilt) von Note 2 gegenüber Note 3.

Dashes with the pigment according to the invention provided against lines with the standard 60-er pigment

• • a higher plucking resistance at offsetting of grade 1 compared to grade 2,
• A higher ink gloss of 82 over 75,
• A slower impact behavior of the printing ink by approx. 15 sec. After the test build-up impact test,
• • better pressure uniformity (visually assessed) from grade 2 to grade 3.

Also produced in the optical and sensory testing using the method according to the invention Papers were found in the test papers excellent quality.

Examples of the milling of CaCO ₃ with coating color:

To produce a calcium carbonate pigment slurry with a fine fraction of more than 90 wt .-% <2 microns was suspended in a ball mill using Calcicell ^® 30, an aqueous anionic copolymer dispersion on the basis of N-butyl acrylate, acrylonitrile and styrene, free of plasticizers and solvents (Acronal ^® S360 D). This polymer dispersion had a solids content of about 50% by weight and a pH of about 8.

The amount of calcium carbonate in the slurry Calcicell ^® 30 was 75 wt .-%. As grinding balls SAZ balls were used with a diameter of 1.6 to 2.5 mm. The net capacity of the mill was 3 l. The power 1.3 kW at a speed of 400 to 1500 U / min.

To the calcium carbonate and water in those listed in Table 1 Amounts, was a concentrated coating color (68.7% solids by weight) added. To prepare the slurry, the batches were each 1% by weight of the abovementioned polymer dispersion (calculation basis filler) added.

Table 1 below shows the experimental program: TABLE 1

The fineness of the materials used was determined by the laser diffraction method with device Cilas: Measurement of the raw calcium carbonate used: D50 4.63 μm D100 27.83 μm <1μm 15,30% <2μm 30.20% Measurement of the coating color used: D50 1.17 μm D100 9.95 μm <1μm 41.50% <2 μm 7 6.10% Example 2: The following analytical results were obtained with pure water: Ball Quantity: 2.0 l of slurry: 0.9 l Rotation speed: about 1100 rpm

The Samples for measuring the particle size distribution were after 20, 40, 60, 80, 100 or 120 minutes taken. While The grinding trial became the mill cooled with water.

Table 2: Evaluation of the Cilas 850/1 measurements:

Color values (measuring device Elrepho) of the filler from the slurry after 120 min:

• Rx = 90.3 / Ry = 90.1 / Rz 0 88.8 / BGW = -1.7 Viscosity measurement (sample after 120 min): Temperature: 20 ° C viscometer: Brookfield HBTD

Table 3: Spindle 2:

Example 3: Table 4: Evaluation of the Cilas 850/1 measurements:

Example 4: Table 5: Evaluation of the Cilas 850/1 measurements:

Color values (measuring device Elrepho) of the filler from the slurry after 110 min:

• Rx = 92.2 / Ry = 92.0 / Rz = 90.7 / BGW = -1.6 Viscosity measurement (sample after 110 min): Temperature: 20 ° C viscometer: Brookfield HBTD

Table 6: Spindle 2:

Example 5: Table 7: Evaluation of the Cilas 850/1 measurements:

Color values (measuring device Elrepho) of the filler from the slurry after 120 min:

• Rx = 92.4 / Ry = 92.2 / Rz = 90.9 / BGW = -1.6 Viscosity measurement (sample after 120 min): Temperature: 20 ° C viscometer: Brookfield HBTD

Table 8: Spindle 2:

Example 6: Table 9: Evaluation of the Cilas 850/1 measurements:

Lighter sieve residue to 40 microns Sieve, foaming, easy bonding of the balls.

Color values (measuring device Elrepho) of the filler from the slurry after 120 min:

• Rx = 91.7 / Ry = 91.6 / Rz = 90.4 / BGW = -1.4 Viscosity measurement (sample after 120 min): Temperature: 20 ° C viscometer: Brookfield HBTD

Table 10: Spindle 2:

Example 7: Table 11: Evaluation of the Cilas 850/1 measurements:

Stronger sieve residue as in Example 6 on the 40 microns Scree. stronger Foaming and stronger bonding the balls.

Color values (measuring device Elrepho) of the filler from the slurry after 120 min:

• Rx = 90.6 / Ry = 90.4 / Rz = 89.1 / BGW = -1.7 Viscosity measurement (sample after 120 min): Temperature: 20 ° C viscometer: Brookfield HBTD

Table 12: Spindle 2:

Table 13: Evaluation of the Cilas 850/1 measurements:

Color values (measuring device Elrepho) of the filler from the slurry after 120 min:

• Rx = 92.0 / Ry = 91.8 / Rz = 90.9 / BGW = -1.2 Viscosity measurement (sample after 120 min): Temperature: 20 ° C viscometer: Brookfield HBTD

Table 14: Spindle 2:

Claims (16)

Process for the preparation of surface-modified inorganic fillers or pigments of defined particle size, characterized in that filler or pigment slurries of inorganic fillers or pigments are ground to the desired particle size under the action of shear forces using polymer dispersions. Method according to claim 1, characterized in that that you are natural and / or precipitated Calcium carbonate, kaolin, artificial and / or natural Aluminum silicates and hydrates, titanium dioxide, satin white, dolomite, Mica, metal, especially aluminum flakes, bentonite, rutile, Magnesium hydroxide, gypsum, phyllosilicates, talc, calcium silicate and other stones and soils or mixtures thereof. Method according to claim 1 or 2, characterized that you have filler or pigment slurries having a filler or pigment content from 10 to 90 wt .-%, in particular 30 to 70 wt .-%, based on the Slurry begins. Method according to one of claims 1 to 3, characterized that use is made of polymer dispersions which are selected from natural and / or synthetic polymers of a particle size in particular from 0.005 to 6 microns in aqueous or non-aqueous Phases. Method according to one of claims 1 to 4, characterized that use is made of polymer dispersions which are selected from natural rubber, synthetic rubber, synthetic resins and plastics, in particular based on polyurethane, styrene / butadiene, styrene / acrylic acid or ester, styrene / butadiene / acrylic acid or esters and vinyl acetate / acrylic acid or esters. Method according to one of claims 1 to 5, characterized that you have the fillers and / or pigments in an amount of 0.1 to 50 wt .-%, in particular 5 to 15 wt .-% polymer dispersion (solid), based on the Amount of pigment brings into contact. Method according to one of claims 1 to 6, characterized that you have the fillers and / or pigments continue to be known per se grinding aids and / or dispersants, especially polyacrylates in contact brings. Method according to claim 7, characterized in that that the dispersants (active substance) in an amount of 0.1 to 2.0 wt .-%, in particular 0.2 to 0.4 wt .-%, based on the fillers or pigments, in contact with them. Method according to one of claims 1 to 8, characterized that the filler and / or pigment slurries with a coating pigment slurry and / or a filler and coating pigment-containing residual water sludge of the spreader effluents, deinking plants, internal sewage treatment plants or separating devices of paper, paint, glue or other Contact factories. Method according to claim 9, characterized in that that coating pigment slurry and / or a filler and / or coating pigment-containing Remaining water sludge with a ratio from fiber fraction to filler and / or pigment content of from 2 to 98% by weight to 98 to 2% by weight. Method according to claim 10, characterized in that that coating pigment slurry and / or a filler and / or coating pigment-containing Residual water sludge with a solids concentration of 0.02 to 80 wt .-%, in particular 20 to 70 wt .-% used. Method according to one of claims 1 to 11 for the production a filler and / or pigment slurry having a solids content of 10 to 95 Wt .-%, in particular 40 to 80 wt .-%. Method according to one of claims 1 to 12, characterized that you have the fillers and / or Pigments of slurries on a particle size distribution of 10 to 99% by weight of particles <10 μm, in particular 10 up to 95% by weight of particles <1 μm, each based on the equivalent diameter, married. Method according to claim 13, characterized in that that you have the fillers and / or pigments of slurries to a particle size distribution of a) 95 up to 100% by weight of particles <20 μm and / or b) 50 to 100% by weight of particles <2 μm, in particular 50 to 95% by weight of particles <2 μm and / or c) From 27 to 99% by weight of particles <1 μm, in particular From 27 to 75% by weight of particles <1 μm and / or d) 0.1 to 65% by weight of particles <0.2 μm, in particular 0.1 to 35% by weight of particles <0.2 μm, each based on the equivalent diameter, married. Surface-modified, inorganic fillers and / or pigments according to a method according to the claims 1 to 14. Use of surface-modified fillers and / or pigments according to claim 15 for the preparation of emulsion paints, Adhesives, coatings or coatings for the paper industry, in particular of paints for various segments, such as sheetfed offset, web offset, gravure, Cardboard and special papers.