EP1125025A1

EP1125025A1 - Aqueous formulation for surface preparation of paper and cardboard

Info

Publication number: EP1125025A1
Application number: EP99947282A
Authority: EP
Inventors: Erik-Andreas Klohr; Volkhard Müller; René Kiesewetter; Jürgen Ramthun
Original assignee: Wolff Walsrode AG
Current assignee: Dow Produktions und Vertriebs GmbH and Co oHG
Priority date: 1998-09-19
Filing date: 1999-09-07
Publication date: 2001-08-22
Also published as: BR9913863A; CN1318120A; HK1041299A1; DE19842962A1; WO2000017449A1; CA2344195A1; JP2002526679A; AU6080199A; KR20010073176A

Abstract

An aqueous formulation for surface preparation of paper and cardboard, comprising a polysaccharide-based co-binder, characterized in that the co-binder contained in said formulation is a water-soluble cellulose derivative that is etherified with sulphoethyl groups.

Description

Aqueous formulation for the surface preparation of paper and cardboard

The invention relates to the use of water-soluble sulfoethyl cellulose ethers, e.g. Sulfoethyl cellulose ether, carboxymethyl sulfoethyl cellulose ether,

Hydroxyethyl sulfoethyl cellulose ether, methyl sulfoethyl cellulose ether, hydroxypropyl sulfoethyl cellulose ether and correspondingly hydrophobically modified sulfoethyl cellulose mixed ether as cobinder for aqueous formulations for the surface preparation of paper and cardboard. Corresponding formulations are also referred to as coating colors.

Water-soluble polyvinyl alcohols, polyacrylamides, polyacrylates, alginates, starches, chitosans, starch ethers, modified starch ethers, non-ionic cellulose ethers, such as e.g. Methyl cellulose ether, hydroxyethyl cellulose ether and hydroxypropyl cellulose ether as well as hydrophobically modified cellulose ether, ionic cellulose ether, such as e.g.

Methyl, carboxymethyl cellulose ether (CMC) and carboxymethyl cellulose ether have long been used as co-binders for pigment-containing coating colors for coating paper and cardboard (see DE 16 21 694, EP 0 399 775, US Pat. No. 4,994 112, EP 0 382 576, US) -PS 5 080 717).

The products used as cobinder have the task of controlling the rheology of the coating color required for the coating process and guaranteeing a uniform coating of the paper or board surface. It is known that when using cellulose ethers, in particular carboxymethyl cellulose ethers, the properties required for the coating process are greater than

The degree of polymerization of the starting cellulose and the degree of substitution of the cellulose ether can be set.

In addition to setting the rheology depending on the respective application unit, the cobinder in pigment-containing coating colors also has the task of preventing the coating color from striking away during the coating process and ensure problem-free processing of the colors. The improvement in water retention is of particular importance here, because it prevents inadmissible increases in the coating color concentration during the coating process and thus longer running times or lower machine downtimes with lower tear-off rates can be set. In addition, more uniform, high-quality coatings can be guaranteed, since the controlled penetration of the additives contained in the coating colors into the base paper during the coating process or during drying can reduce migration processes of coating color components in the coating (see JS Malik, JE Kline, Tappi 1992, Coating Conference Proceedings

Tappi-Press, Atlanta, pp. 105 to 113).

According to the prior art, the rheology of coating colors and. a. with the type and amount of pigment (e.g. chalk and / or kaolin) and the binder or cobinder (e.g. CMC). When using CMC as a cobinder, improved values for the dynamic water release capacity of the coating color or the quality of the surface coating of the papers can be obtained by increasing the amount of cobinder in quantitative terms or by providing a CMC with a higher degree of substitution by carboxymethyl groups of approximately 1 or above . However, these options are associated with economic disadvantages both for the manufacturer of the CMC and for the paper refiner itself, since the improved properties can only be achieved by using larger amounts of raw materials (lye, chloroacetic acid) or longer reaction times in the alkalization or etherification let the cellulose adjust.

Improved values for the dynamic water release capacity of the coating color can also be achieved by increasing the molecular weight or the viscosity of the CMC used. However, high molecular weight carboxymethyl cellulose ethers can only be processed to a limited extent, since an excessively high increase in viscosity in the coating color must be avoided, since this would otherwise lead to processing problems in the form of

Squeegee strips, web breaks and. Ä. can come. When using highly viscous carboxy As a rule, methyl cellulose ethers for coating color can only be used in low-concentration CMC solutions. However, this in turn leads to a deterioration in the quality of the coated papers (for example a decrease in paper whiteness etc.). If high-molecular cobinder is added in the form of aqueous solutions, there is also an undesirable high entry of water into the pigment coating color. The result is lower solids contents of the pigment coating color or longer drying times of the coated paper or cardboard web and thus higher energy costs for the user with lower paper throughputs.

The trend towards ever higher machine speeds and the tendency to increasingly use a pigment with calcium carbonate, the use of which without the kaolin, which has often been used up to now, leads to significantly poorer water retention of the coating color, make the need clear, qualitatively improved products with lower dynamic To provide water delivery capacity. The addition of such an improved cobinder to the pigment coating color should also not be accompanied by inadmissible increases in the viscosity of the paint. Furthermore, the introduction of new types of cobinder should not impair the quality of the coated paper.

Surprisingly, it has been found that the use of alkylsulfonated and hydroxyalkylsulfonated, carboxy-polysaccharides or mixed ethers such as sulfoethyl cellulose derivatives, in particular sulfoethyl cellulose ethers (SEC), carboxymethyl sulfoethyl cellulose ethers, methyl sulfoethyl cellulose ethers, methyl hydroxyl ether, hydroxyl methyl sulfoxethyl cellulose -Sulfoethyl cellulose ethers, ethyl sulfoethyl cellulose ethers, hydroxyethyl sulfoethyl cellulose ethers and hydroxypropyl sulfoethyl cellulose ethers as cobinder improve the quality of coating colors. It has been found that coating colors containing cobinder based on sulfoethyl cellulose, with the same solids content and the same viscosity, show lower values for the dynamic water release capacity with improved rheology than coating colors with CMC as cobinder. Furthermore the use of hydrophobically modified sulfoethyl cellulose mixed ethers, such as hydroxypropyl sulfoethyl cellulose ether, leads to an improvement in the quality of the paper during printing.

This effect is among others a function of the raw material, the sulfoalkylation reagent and the level of the degree of substitution (DS) determined by the sulfoalkyl group. Hetero- and homo-polysaccharides, such as e.g. Celluloses (e.g. cellulose chemical pulps, linters, raw linters, softwood sulfates, softwood sulfate and / or hardwood pulps), galactomannans (guar, carob bean gum), starches (corn, potato, wheat starches etc.) and theirs

Hydrolysates or enzymatically, thermally and / or oxidatively degraded products, pectins, carraghenans, alginates, xanthan, hemicelluloses, chitin and chitosans are claimed. Sulfoalkyl-modified proteins, such as e.g. Gelatin and others claimed.

The average molecular weights [M _w ] (multi-angle laser light scattering photometer DAWN, Wyatt) of the sulfoalkylated polysaccharide ethers claimed according to the invention are max. 10 ⁸ [g-mok ¹ ], preferably at max. 200,000 [g-moH].

Compounds commonly described in the literature, such as e.g. Chloromethylsulfonic acid, chloroethanesulfonic acid, chloropropanesulfonic acid, 1,3-propanesulfone, vinylsulfonic acid or sodium vinylsulfonic acid or the like claimed.

The sulfoalkylated polysaccharide ethers claimed according to the invention are prepared and packaged in the manner generally known to those skilled in the art. The sulfoalkylated polysaccharide ethers can be added as monosaccharide ethers as powder, granules or as a suspension for the formulation of coating colors. For technological or economic reasons it may be necessary to react the monoethers in further synthetic steps with conventional long- or short-chain alkyl- or alkyl-aryl-, carboxyalkyl- or hydroxyalkyl group-transferring reagents. Gentien, such as methyl chloride, ethyl chloride or long-chain glycidyl ethers, chlorinated or bromocarbons with 3 to 30 carbon atoms; Chloroacetic acid or sodium chloroacetic acid; Ethylene, propylene or butylene oxide, further to convert to binary or ternary mixed ethers.

It is also possible to mix the monoethers claimed according to the invention or the binary or ternary mixed ethers with conventional water-soluble, unmodified polysaccharides, such as e.g. Starches, alginates or galactomannans, or water-soluble, modified polysaccharides, in particular polysaccharide ethers, such as e.g. Starch ethers (e.g. carboxymethyl starch,

Use methyl starch, ethyl starch, hydroxyethyl starch, hydroxypropyl starch), cellulose ethers (e.g. methyl cellulose, ethyl cellulose, methylhydroxyalkyl cellulose, hydroxyalkyl cellulose, car oxymethyl cellulose, carboxymethyl hydroxyethyl cellulose etc.), galactomannan ethers (e.g. carboxymethyl guar, hydroxypropyl guar).

The use amount of the cobinder claimed according to the invention or the physical mixture claimed according to the invention in the coating color formulation is not subject to any restrictions. However, it is usually made dependent on technical (viscosity) or economic factors. The proportion of cobinder added to the coating color is usually max. 10 parts based on 100 parts pigment, especially at max. 2 parts, preferably at max. 1st chapter.

When using cellulose-based cobinder as an additive for pigment-containing coating colors, preference is given to using those cellulose ethers which have the highest possible solution quality. Gel particles, fibers and specks can clog filters and sieves. If coarser, water-insoluble cellulose particles get stuck under the coating unit, doctor strips or web breaks can occur. It is therefore necessary to use cellulose ethers that are soluble in water without gel bodies, fibers and specks. The water solubility of Cellulose ethers are usually adjusted via the level of substitution of the etherification components.

In the case of the cellulose ethers claimed according to the invention and further described by way of example, the “DS” (degree of substitution) denotes the average number of hydroxyl groups substituted in the cellulose per anhydroglucose unit. According to the invention, it is advantageous if the DS by cellulose ethers used is less than 1.2 by sulfoethyl groups It is known to the person skilled in the art that for the production of a water-soluble CMC a degree of substitution of approximately 0.4 or for the production of a water-soluble, not further substituted SEC the level of the substitution must be at least approximately 0.2-0.3. For aqueous formulations according to the invention with SEC without further substituents, the DS of the SEC is preferably 0.2 to 0.9, in particular 0.3 to 0.75. The degree of substitution is generally significantly higher for the production of fiber-free solutions (see EP 0 319 867 In the case of mixed ethers containing sulfoethyl groups, this is to achieve the water solubility required degree of substitution by sulfoethyl groups significantly lower. For the mixed ethers used in the formulations according to the invention, the degree of substitution (DS) by sulfoethyl groups is preferably 0.05 to 0.9, in particular 0.01 to 0.8 and particularly preferably 0.1 to 0.7.

The aqueous formulation according to the invention can contain one or more auxiliaries according to the prior art, preferably from the group of dispersing auxiliaries (in particular polyphosphates, polyacrylates), binders (in particular starch and starch ethers, casein, polymer dispersions based on butadiene-styrene, acrylic acid ester styrene, acrylic acid ester) Vinyl acetate, vinyl acetate-ethylene and copolymers of the above products with acrylonitrile), anti-foaming agents (in particular emulsions of animal or vegetable fats, silicone emulsions or higher alcohols and their esters), optical brighteners and acceptors therefor (in particular polyvinyl alcohols, casein, CMC), shading dyes (in particular pigment colors Substances, nouns and basic dyes) to adjust the color locus, products to increase water resistance (especially melamine and urea resins, Glyoxal, epoxy resins) and / or auxiliaries that are required for the finishing of the coated paper (in particular calcium, sodium or ammonium stearate, wax dispersions, polyglycols and polyethylene dispersions). The pigments in pigment-containing coating colors are the raw materials familiar to the person skilled in the art, such as kaolin, natural calcium carbonate, talc, satin white, precipitated calcium carbonate, titanium dioxide, aluminum hydroxide, gypsum, barium sulfate, plastic or plastic pigments alone or as a mixture in dry or already predispersed form ( so-called slurry form).

In a further embodiment of the invention, the aqueous formulation is a so-called sizing agent which contains the cobinder in a pigment-free formulation, optionally together with one or more of the above-mentioned auxiliaries. It is preferably an aqueous solution which contains the sulfoethyl cellulose ether in a concentration of 0.1 to 30%, in particular 0.1 to 15%.

The cobinders used in the examples were added to the pigment slurry as highly concentrated, aqueous solutions. The aqueous solutions of the sulfoethyl cellulose derivatives claimed according to the invention all have high transmission values of T> 95% (2% by weight aqueous solution, wavelengths of the used

Light λ = 550 mm, optical path length of the cuvette = 10 mm) [Hitachi spectrophotometer, model 101, Hitachi Ltd. Tokyo-Japan). The setting of low fiber contents of <1% can thus be guaranteed.

A dynamic measuring method is used to determine the dynamic water release, the rheology and the immobilization of the coating colors, as described in the literature (see Das Papier 50 (1996), No. 3, 97 ff).

The cellulose ethers designated in Table 1 are used for the experiments described below. The preparation of the sulphates claimed according to the invention Foethyl cellulose derivatives are known from the literature (see US Pat. No. 2,811,519; US Pat. No. 4,972,007; EP 0 319 865 A2).

Table 1: Characteristics of the products used to determine water retention

Brookfield RVT, 100 rpm, T = 25 ° C, atro, target viscosity range: 800 -

1600 mPa.s (c = 10%) for Walocel CRT 5 G and corresponding samples

Average degree of substitution by sulfoethyl, carboxymethyl [DS] and hydroxypropyl groups [MS]

3) pH value of 10% aqueous solutions 4) merchandise from Wolff Walsrode AG

The products referred to in Table 1 are coated with kaolin and

Chalk incorporated as pigment according to the standard formulation listed in Table 2. The rheological behavior and the initial water release using a dynamic measurement method are examined. The standard wording is first the recipe listed in table 2 is used. However, this does not imply a restriction to the recipe components described here.

Table 2: Standard coating color formulation for investigations of the water release capacity

i) Amazon 88, Kaolin International B.V .; Holland

2) Hydrocarb 90, Omya; Germany and Plüss Staufer; Switzerland 3) Baystal P 8588, Polymer Latex GmbH; Germany 4) Blankophor P liquid, Bayer AG; Germany 5) calcium stearate, from Henkel KGaA; Germany

The results of the investigations into the rheology and the initial water release capacity under dynamic measuring conditions with 0.3 parts of cobinder each per 100 parts of pigment are shown in Table 3. Table 3: Comparison of rheology and initial water release (WAV) of coating colors

i) Sample name s. Table 1

2) Solids content of the paint 3) Proportion of cobinder in the formulation listed in Table 2 4) Low-Shear Haake CV 100, viscosity run-up at a shear rate of

Gamma point = 300 1 / s

Low-Shear Haake CV 100, viscosity after 10 min shear time at a

Shear rate of gamma point = 300 1 / s

Water release capacity (WAV) at 5 bar at time t = 0 min [= immediately]

Basically, the tendency in the production of coated graphic papers is to use coating colors with the lowest possible water content, i.e. high solids content. Energy savings during drying, higher throughputs and more voluminous coating layers can be achieved in this way. In order to ensure the flowability of such a paint, the viscosity and the water release, in particular the initial water release of a coating color, should be low. This minimizes the risk of a sudden increase in the viscosity and thus the solids content of the coating color during the coating process. If the water retention of the ink is in a critical range, the pressure impulses of approx. 2 - 4 bar effective under the coating unit can lead to a sudden increase in the solids content under the squeegee due to the water penetrating too quickly into the paper. This leads to so-called scraper boiling over or to beard formation, i.e. deposits of the coating color on the coating unit, squeegee strips or tearing of the paper web.

After the coating process, the immobilization of the

Coating color, so that all transport processes of formulation components present in the formulation are prevented. If this process takes too long, migration processes can be triggered both into the paper and onto the paper surface, which can lead to a loss of quality when printing (eg mottling). In the experiments carried out here to investigate the water retention of coating colors, a dynamic measurement method as described in the literature was used (see DW Jones et al. In: Das Papier, 50 (3) (1996) pp. 97-106) . The procedure is such that the coating color to be examined is entered into the aforementioned measuring cell and sheared under defined conditions.

The amount of water released is recorded as a function of the solids content currently present in the paint. The value for the amount of water delivered at time t = 0 is referred to as the initial water delivery. The results in Table 3 show that the coating colors formulated with sulfoethyl cellulose ethers (serial numbers 3 to 6) are in contrast to the standard (Walocel CRT 5 G (= status of

Technology)) have improved dynamic water delivery capacity at 5 bar. In comparison to coating colors formulated with CMC, surprisingly, sulfoethylated polysaccharides such as e.g. Sulfoethyl cellulose, hydroxypropyl sulfoethyl cellulose, sulfoethyl guar, hydroxypropyl sulfoethyl guar (see Table 3) and others. to a liquefying effect in the coating color. The products in water retention are at a consistently high level. It is striking that the viscosities determined are still significantly lower than those of the unthickened coating color (cf. Table 3, current No. 1 with No. 3 to 6 and current No. 7 with No. 9). Particularly in the case of highly pigmented, particularly critical formulations, such as those described under Nos. 7-9, this leads to the ones described above

Advantages. Example No. 8 shows that the water release capacity of the coating slip formulated with sulfoethyl cellulose is significantly below that of the standard (see current No. 8 and 9). Despite a similar viscosity level of the aqueous solutions (see Table 4), the viscosity of the coating thickened with SEC is clearly below the level of the reference sample and the unthickened ink.

In contrast to the reference sample (Walocel CRT 5 G [Table 3, current numbers 2 and 8]), the coating inks formulated with sulfoethyl cellulose ethers also lead to faster immobilization of the ink. This minimizes the risk of migration processes from, for example, binder components to the surface of the coating. Machine tests were carried out on a coating system with the products described in Table 4.

Table 4: Characteristics of the Cobinder used for machine tests

Brookfield RVT, 100 rpm, T - 25 ° C, dry, c = 10%, target viscosity: 800 to 1600 mPa.s (No. 1 + 3) or 300 - 450 mPa.s (No. 2, 4 , 5)

2) Degree of substitution by sulfoethyl or hydroxypropyl groups (MS) 3) pH value in 10% solutions 4) Merchandise from Wolff Walsrode AG 5) Sulfoethyl cellulose ether

The products Walocel CRT 5 G and Walocel CRT 3 G were used as standards

(both carboxymethyl cellulose ether) used. These were compared to sulfoethyl cellulose ethers (SEC 1 and 6) or hydroxypropyl sulfoethyl cellulose ether (HP SEC). The cobinders were incorporated into the standard formulation described in Table 5 in an already predispersed pigment slurry with the additives described below. A wood-containing LWC paper (36 g / m ² ) was used as the base paper. At speeds of the coating machine of approximately 1,600 m / min, approximately 9 g / m ^{2 of} coating color were applied to the paper surface. The application was carried out on both sides (first screen top, then screen side) with a doctor blade system (stiff blade). A

However, this does not imply a restriction to such order systems. Other application units, such as In principle, roller, jet or spray units can be used.

The coated papers were then dried and satined and in the

Printed roll offset process. The results on rheology, immobilization and the dynamic water release capacity are shown in Table 6.

Table 5: Machine tests / recipe ¹ '

Target speed: 1600 m / min

Order for top and screen side: 9 g / m ²

Moisture for top and screen side: 4 or 5.5%

Blade (SB): 0.457 / 40 ° (tip 3 °)

Drying process IR / AIF: after 1st IR break (+ AIF falling)

Calender: 600 m / min; Nip: 11, N / mm: 160, temperature (H1 / H2): 90/90 ° C

2) FSG ≡ solids content, which was initially set everywhere for the top of the sieve

VI contains Walocel CRT 5 G (standard) compared to V2 (SEC 1 as cobinder);

V5 contains Walocel CRT 3 G (standard) compared to V3 (HPSEC) and V6 (SEC

6 as cobinder) 4) FSG ≡ solids content, which was initially set everywhere for the top of the sieve

Recipe components were obtained from the manufacturers listed in Table 2.

In contrast to the preliminary tests to determine the water release capacity under dynamic measuring conditions, the aim of the practical tests was to set coating colors with the highest possible solids content in order to be able to assess the running behavior during the coating process under realistic conditions. The first attempt was to apply the coating colors with a solids content of 69.0% to the paper surface. When the top of the sieve was first coated, the solids content had to be reduced during the experiment, since theological problems caused by scraper boiling over and the like. came. The results of the coating on the sieve side (SS) should therefore be used to assess the samples with one another (Table 6).

Table 6: Results on the rheology and the dynamic water release capacity (WAV) of the coating colors used for machine tests

1) See table 5 for samples; SS = Sieve side 2) Solids content of the paint 3) Low-Shear Haake CV 100, viscosity ramp-up at gamma point = 300 1 / s 4) Low-Shear Haake CV 100, viscosity after 10 min shear time at gamma point

= 300 1 / s

5) Water release capacity (WAV) at 3 bar at time t = 0 6) Solids content difference to the reference sample

All information on the solids content (FSG), the pH value and the viscosity refer to the final value (≡ sieve side) on the application unit.

The results of the preliminary tests, according to which lower thickening capacities or more liquefying effects are associated with sulfoethyl cellulose derivatives approved. The results of the tests carried out with SEC No. 1, SEC No. 6 and HPSEC (see Table 6, current No. 2, 4, 5) show that higher solids contents of approximately 1.5-2% can be set anywhere . In this way, practically identical color viscosities are obtained in comparison with the respective reference samples (see Table 6, serial numbers 1 and 3). While the dynamic water release capacity at 3 bar provides similar values everywhere, the use of coating colors thickened with sulfoethyl cellulose derivatives is associated with significantly shorter immobilization times. The advantages of drying or subsequent coating in this regard have already been mentioned above.

While at the beginning of the coating tests the solids content had to be reduced by adding water to avoid problems during application due to deposits on the application unit (e.g. scraper boiling over, stalagmite formation etc.), the color application of the screen side was with a more even running behavior of the paper web connected. The solids contents for the coating tests on the sieve side were practically constant throughout the test (see Table 7, comparison of start and end).

Table 7: Machine tests ³ '/ results on sieve side ^l) (≡ end of test)

Results for the screen side (≡ end of test) pH values of the colors everywhere 8.6 - 8.8; Cf. No. VIB (blank) with V2; V5

(Zero test) with V3 and V6

2) Viscosity using Brookfield RVT, 100 RPM, T = 28 ° C 3) Coating machine speed: 1600 m / min

The results of the paper tests on uncalendered and calendered paper are shown in Tables 8 and 9.

Table 8: Results of the paper tests on uncalendered paper / NESTRA (screen side) (≡ end of test) ^l

Results for the sieve side (≡ end of test) cf. Νr. VIB (zero sample) with V2; V5 (zero test) with V3 and V6

Table 9: Results of the paper tests on calendered paper / NESTRA (screen side) (≡ end of test) ^l)

⁰ results for the sieve side (≡ end of test) cf. Νr. VIB (zero sample) with V2; V5 (zero test) with V3 and V6

The differences between the samples are all within the standard deviations for the paper tests. The coating colors or papers coated with different co-binders were then printed in roll offset. The results of the printability tests are shown in Table 10.

Table 10: Results of the offset prints

Results sieve page; Color: 408020; compare: VIB (standard) with V2; V3 with V5 (standard) and V6

2) color: 408002 3) color: 520068 4) color: 408010; 0 = no mottling, 1 = low mottling, 2 = light mottling

5) Roll offset, 54 g / m ² coated and satined on both sides, roll width: 0.57 m (76 mm sleeves), type: Rotoman C (MAN), speed: 25,000 sheets / h (approx.4.4 ms), Dryer length 10 m (3 sections), inking units: 4 / beautiful and Reprint, color sequence: black / cyan / magenta / yellow (Huber standard LWC colors [Michael Huber GmbH, Munich]), dampening solution composition: isopropanol content 13% (pH = 4.8) (dampening solution addition Hydrofix A 8085- 09.2%)

With regard to the gloss, values of a minimum of 23% and a maximum of 26% are obtained for the screen side. The values for the optical density are in the range from 1.39 to 1.45 and therefore show only slight differences. The standard color no. 408002 causes individual line particles to break out on all papers. In contrast, the softer color with No. 408001 does not pick. The pick resistance of the papers is everywhere in the critical range. However, it is not possible to differentiate the patterns from one another, since their quality is at a uniform level. All papers show quick set-off behavior, which has a positive effect on ink drying.

When assessing the pressure drop, the tests labeled V2 and V6 are assessed as particularly positive. In particular, the ink (V3) formulated with hydroxypropyl sulfoethyl cellulose shows advantages when printing.

In the context of the conditions specified for the tests (web temperature 120-150 ° C.), the sudden escape of water vapor from the coating surface or the base paper, known as blistering, was not observed in any of the tests.

Claims

claims

1. Aqueous formulation for the surface preparation of paper and cardboard with a cobinder based on polysaccharide, characterized in that the formulation contains as a cobinder a water-soluble cellulose ether etherified with sulfoalkyl groups, especially sulfoethyl groups.

2. Aqueous formulation for the surface coating of paper and cardboard according to claim 1, characterized in that the cobinder is a sulfoethyl cellulose ether with a degree of substitution by sulfoethyl groups of less than 1.2, preferably in sulfoethyl cellulose 0.2 to 0.9 or with mixed ethers 0.005 to 0.9.

3. Aqueous formulation for the surface coating of paper and cardboard according to one of claims 1 or 2, characterized in that it is in the etherified with sulfoethyl cellulose derivative carboxymethyl sulfoethyl cellulose, methyl sulfoethyl cellulose, methyl hydroxyalkyl sulfo ethyl cellulose, methyl hydroxypropyl sulfoethyl cellulose, hydroxy -ethyl sulfoethyl cellulose or hydroxypropyl sulfoethyl cellulose.

4. Aqueous formulations for the surface coating of paper and cardboard according to one of claims 1 to 3, characterized in that the cobinder is sulfoethyl cellulose with a degree of substitution by sulfoethyl groups from 0.3 to 0.75 or carboxymethyl, methyl, methyl - hydroxyethyl, methylhydroxypropyl, hydroxyethyl or hydroxypropyl

Sulfoethyl cellulose with a degree of substitution by sulfoethyl groups of 0.01-0.7, in particular 0.1-0.7.

5. Aqueous formulation for the surface coating of paper and cardboard according to one of claims 1 to 4, characterized in that the form contains at least one pigment, in particular calcium carbonate, kaolin, gypsum, titanium dioxide or mixtures thereof.

6. Aqueous formulations for the surface coating of paper and cardboard according to one of claims 1 to 4, characterized in that the

Formulation is pigment-free and contains the cobinder alone or together with other auxiliaries.

7. Aqueous formulation for the surface coating of paper and cardboard according to claim 6, characterized in that the used as a cobinder

Sulfoethyl cellulose ether in an aqueous solution with a concentration of 0.1-30%, in particular 0.1-15%, is used.