EP1904418A2

EP1904418A2 - Use of carboxylate-containing polymers as additives in ceramic materials

Info

Publication number: EP1904418A2
Application number: EP06764036A
Authority: EP
Inventors: Joachim Pakusch; Marcus Guzmann; Thorsen Wiedemann; Stefan Becker; Marco Schmidt; Thomas GÖTZ; Gregor Brodt
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2005-07-14
Filing date: 2006-07-04
Publication date: 2008-04-02
Also published as: MX2008000633A; WO2007006683A3; CA2615234A1; RU2413700C9; RU2008104960A; RU2413700C2; BRPI0613035A2; DE102005033518A1; WO2007006683A2; CN101263094A; US20090105390A1

Abstract

The invention relates to the use of homopolymers or copolymers of (meth)acrylic acid or copolymers of C3-C40 monoolefins with ethylenically unsaturated C4-C6 dicarboxylic acid anhydrides as additives in ceramic materials, especially in clay, in order to produce ceramic construction materials, such as bricks and roofing tiles as well as ceramic materials containing said additives.

Description

Use of carboxylate-containing polymers as additives in ceramic compositions

The present invention relates to the use of homopolymers or copolymers of (meth) acrylic acid or copolymers of C ₃ -C ₄₀ monoolefins with ethylenically unsaturated CU-Ce-dicarboxylic anhydrides as additives in ceramic compositions, in particular in loam and clay for the production of Building ceramics, such as bricks and roof tiles as well as ceramic masses containing these additives.

The production of bricks from clay is practiced worldwide. All processes involve the degradation of suitable clay or clay, the crushing and / or grinding of the clay into a suitable size, and the mixing of the material with sufficient water to render the clay or plastic workable.

Clay is an earthy mineral aggregate consisting predominantly of hydrous aluminum silicates which are plastically deformable when wet, rigid in the dry state and become glassy when heated.

As a clastic sediment, clay is a mixture of various minerals, mainly composed of clay minerals, aluminum hydrosilicates and hydrates, quartz, feldspar, gypsum, etc. Clay minerals essentially comprise kaolinite, halloysite, montmorillonite, illite and chlorite. Clay is plastically deformable in the wet state, rigid in the dry state and becomes transparent when heated.

The clay or clay is mined according to its occurrence, and transported to brickworks for further processing into bricks.

In processing operation, water is added to adjust the moisture content or to increase plasticity, and the clay / clay is then temporarily stored for swelling. For further processing, the raw material is then ground to achieve a small particle size, typically less than 1mm, as a rule. Subsequently, a moisture content of, for example, 20% is set with water so that the material becomes plastically processable. Additives or the polymers according to the invention can also be added in this step. The polymers according to the invention lead to increased plasticity as well as increased mechanical strength of the dried products. The additivated clay is then extruded by molding. This is followed by drying at temperatures greater than 100 ° C. Optionally, the moldings are then engobed or coated. Then the firing process takes place at temperatures up to 110o ⁰ C. After firing, the finished products are cooled.

WO 01/09058 discloses a mixture containing clay, water and a tannin or a tannin derivative and a method for producing bricks using the claimed mixture.

JP 10-194844 describes the production of ceramic shaped bodies, containing not only clay but also cement using maleic acid copolymers.

US 3,061,564 discloses graft polymers based on shellac and acrylic monomers.

US 4,148,662 and GB 2041950 disclose a mixture for the production of bricks as well as a method for producing bricks using water-soluble anionic polyelectrolytes.

In the practice of brick making clay or clay, the water content is a critical size. If the water content is too high, the bricks may deform during stacking, resulting in long drying times and undesirable shrinkage during the drying process. By far, the mechanical stability of the dried products is relatively low, so that easily damage occurs and thus the committee is increased.

On the other hand, if the water content is too low, the plastic processability is too low, which makes shaping impossible or can cause the bricks to crumble during further processing. An additive which, when added in small amounts, can significantly reduce the water requirement of the clay to achieve plastic processability, can lead to considerable energy, time and cost savings as well as by increasing the mechanical stability of the dried moldings to reduce product scrap in the production of molded parts to lead.

Object of the present invention was therefore to reduce the water content of clay or clay to achieve the plastic processability and increasing the mechanical strength of the dried molded body.

The object was achieved by the use of (a) (meth) acrylic acid copolymers containing

(I) 50 to 100 wt .-%, of a poly (meth) acrylic acid skeleton and

(ii) 0-40% by weight, of at least one unit bonded to the skeleton and / or incorporated in the skeleton, selected from the group consisting of isobutene units, terelactone units and isopropanol units and

(iii) 0 to 50% by weight of sulfonic acid group-containing units, and

(iv) optionally other units which can be derived from ethylenically unsaturated monomers, wherein the total weight of the units in the

(Meth) acrylic acid copolymer is 100 wt .-% or of

(b) Copolymers of

(i) C ₃ -C ₄₀ monoolefins with (ii) ethylenically unsaturated C ₄ -C ₆ dicarboxylic acid anhydrides

as additives in ceramic compositions, especially in loam and clay for the production of building ceramics, such as masonry and roof tiles.

Another object of the invention are ceramic compositions containing these additives, in particular clay and clay tiles containing these additives.

For the purposes of the present invention, the term (meth) acrylic acid copolymers means methacrylic acid polymers, acrylic acid polymers and mixed polymers of methacrylic acid and acrylic acid. In a preferred embodiment of the invention, the polymer according to the invention comprises a polyacrylic acid skeleton.

For the purposes of the present invention, terelactone units are understood as meaning units of the following structure:

Homopolymers of acrylic acid and methacrylic acid are known. They are prepared, for example, by polymerizing acrylic acid or methacrylic acid in aqueous solution in the presence of polymerization initiators and optionally polymerization regulators at temperatures of 50 to 150 ° C. At temperatures above 100 ° C, it is necessary to carry out the polymerization in pressure equipment. The molecular weights of the polyacrylic acids and polymethacrylic acids to be used according to the invention are from 500 to 100 000 g / mol and are preferably in the range from 800 to 40 000 g / mol.

Likewise, copolymers of acrylic acid and methacrylic acid, which may contain the two monomers in any ratio, use according to the invention. The molecular weight range of the copolymers of acrylic acid and methacrylic acid corresponds to that of the homopolymers.

The determination of the weight average molecular weight is carried out by GeI

Permeation chromatography (GPC) at room temperature in aqueous eluents)

If appropriate, the novel polymers (a) may additionally comprise units (iv) of other ethylenically unsaturated monomers copolymerizable with (meth) acrylic acid. Suitable monomers for this purpose are, for example, monoethylenically unsaturated carboxylic acids such as maleic acid, fumaric acid, itaconic acid, mesaconic acid, methylene malonic acid and citraconic acid. Further copolymerizable monomers are C 1 to C ₄ alkyl esters of monoethylenically unsaturated carboxylic acids, such as methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate and hydroxybutyl acrylate. Also suitable as monomers are alkylpolyethylene glycol (meth) acrylates which are derived from polyalkylene glycols having 2 to 50 ethylene glycol units, monoallyl ethers of polyethylene glycols having 2 to 50 ethylene glycol units and allyl alcohol. Further suitable monomers are acrylamide, methacrylamide, N-vinylformamide, styrene, acrylonitrile, methacrylonitrile and / or monomers carrying sulfonic acid groups and also vinyl acetate, vinyl propionate, allyl phosphonate, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylimidazole, N-vinyl-2-one. methylimidazoline, diallyldimethylammonium chloride, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate. The basic monomers such as dimethylaminoethyl methacrylate can be used for example in the form of the free bases, as salts with strong acids such as hydrochloric acid, sulfuric acid or phosphoric acid or in the form of quaternized compounds as comonomers. Likewise, the above-mentioned acid group-containing monomers can be used in the form of the free acids or as salts, for example the sodium, potassium or ammonium salts in the polymerization. Preferably, polymers according to the invention are present in neutralized form. Likewise, sulfonic acid monomers or their salts can also be copolymerized directly. The sulfonic acid monomers are preferably selected from the group consisting of 2-acrylamidomethyl-1-propanesulfonic acid, 2-methacrylamido-2-methyl-1-propanesulfonic acid, S-methacrylamido-hydroxypropanesulfonic acid, allylsulfonic acid, methallylsulfonic acid, allyloxybenzenesulfonic acid, methallyloxybenzenesulfonic acid, 2-hydroxy-3 - (2-propenyloxy) propanesulfonic acid, 2-methyl-2-propene-1-sulfonic acid, styrenesulfonic acid, vinylsulfonic acid, 3-sulfopropyl acrylate, 3-sulfopropyl methacrylate, sulfomethylacrylamide, sulfomethylmethacrylamide and their water-soluble salts.

The (meth) acrylic acid copolymer of the present invention may have at least one unit bonded to the poly (meth) acrylic acid skeleton selected from the group consisting of isobutene units, terelactone units and isopropanol units. When isobutene units are contained in the polymer of the present invention, their amount is, for example, 0.5 to 3.0 mol%. In further embodiments, the amount of isobutene units present may be 0.8 to 2.5 mole% or 1.0 to 2.0 mole%.

The terelactone units can be present both terminally and in the polymer chain.

The (meth) acrylic acid copolymers according to the invention may additionally have at least one of the following structural units:

CH, CH,

\ I ³ \ I ³

HC-CH HC-C -

/ \ / I

CH, CH,

^{3 3} (I).

The amide units based on aminoalkylsulfonic acids can be derived from any aminoalkylsulfonic acid. Particularly suitable aminoalkylsulfonic acids are those having 2 to 12, preferably 4 to 10 carbon atoms. The amino groups may be primary, secondary or tertiary. As further substituents, the aminoalkylsulfonic acids may, for example, have hydroxyl or alkoxy groups or halogen atoms. The alkyl groups may be unsaturated or preferably saturated, straight or branched or closed to the ring. The amino groups may be located within the chain of aminoalkyl groups or as side or terminal substituents. They may also be part of a preferably saturated heterocyclic ring. In a further embodiment of the present invention, the (meth) acrylic acid copolymer according to the invention contains the structural unit (II) based on aminoethanesulfonic acid (taurine):

X ⁺ O ₃ S

In general, the sulfonate moieties of the (meth) acrylic acid copolymers can be saturated with any counterion. Preferably, the counterion is selected from the group consisting of protons, alkali ions or ammonium ions.

The sulfoalkylamide structural units are preferably randomly distributed in the (meth) acrylic acid copolymer.

If the polymers (a), groups (i) and (iii) (polymer A) or (ii) and (iii) (polymer B) of the invention are prepared by the following process steps:

(1) free radical polymerization of (meth) acrylic acid in water in the presence of (i) and (iii) or in the presence of (ii) and (iii) in the presence of isopropanol or isopropanol and water, and

Amidation of the polymer A from process step (1) by reaction with at least one aminoalkanesulfonic acid.

This process is suitable, for example, for the preparation of the (meth) acrylic acid copolymers according to the invention described above.

The process step (1) is performed at temperatures of preferably 100 to 200 ⁰ C, particularly preferably 105 to 135 ° C, in particular 120 to 125 ° C is performed.

Process step (1) is preferably carried out in a closed reaction vessel, for example an autoclave. The pressure in process step (1) thus generally results from the vapor pressure (autogenous pressure) of water or, if appropriate, isopropanol or isopropanol / water mixtures at the abovementioned temperatures. independence this may possibly also be carried out under additional pressure or under reduced pressure.

Process step (1) can be carried out in isopropanol or in at least 20% by weight, particularly preferably at least 25% by weight, in particular at least 30% by weight, of isopropanol-containing aqueous solutions.

The radical polymerization of the monomers is preferably carried out using hydrogen peroxide as an initiator. However, all compounds which form radicals under the reaction conditions, for example peroxides, hydroperoxides, peroxydisulfates, peroxodicarboxylic acids, peroxycarboxylic acid esters and / or azo compounds, can also be used as polymerization initiators.

Optionally, additional monomers can be used in process step (1) of the process according to the invention, for example, with (meth) acrylic acid copolymerizable ethylenically unsaturated monomers. Suitable comonomers are, for example, monoethylenically unsaturated carboxylic acids, such as maleic acid, fumaric acid, itaconic acid, mesaconic acid, methylenemalonic acid and citraconic acid. Further copolymerizable monomers are C 1 - to C ₄ -alkyl esters of monoethylenically unsaturated carboxylic acids, such as methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate and hydroxybutyl acrylate. Also suitable as comonomers are alkylpolyethylene glycol (meth) acrylates which are derived from polyalkylene glycols having 2 to 50 ethylene glycol units, monoallyl ethers of polyethylene glycols having 2 to 50 ethylene glycol units and allyl alcohol. Further suitable monomers are acrylamide, methacrylamide, N-vinylformamide, styrene, acrylonitrile, methacrylonitrile and / or monomers carrying sulfonic acid groups and also vinyl acetate, vinyl propionate, allyl phosphonate, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylimidazole, N-vinyl-2-one. methylimidazoline, diallyldimethylammonium chloride, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate. The basic monomers such as dimethylaminoethyl methacrylate can be used for example in the form of the free bases, as salts with strong acids such as hydrochloric acid, sulfuric acid or phosphoric acid or in the form of quaternized compounds as comonomers. Likewise, the abovementioned monomers containing acid groups can be used in the form of the free acids or as salts, for example the sodium, potassium or ammonium salts, in the polymerization. In a particular embodiment of the present invention, the proportion of (meth) acrylic acid in the polymer B is 75 to 95 wt .-%, preferably 80 to 90 wt .-%, particularly preferably 82.5 to 87.5 wt .-%. The proportion of units based on isopropanol in the polymer B is then preferably from 5 to 25% by weight, particularly preferably from 10 to 20% by weight, in particular from 12.5 to 17.5% by weight.

The polymer B obtainable by process step (1) of the process according to the invention optionally has isobutene units in an amount of preferably 0.5 to 3.0 mol%, particularly preferably 0.8 to 2.5 mol%, in particular 1, 0 to 2 , 0 mol%, on. The isobutene units may optionally be arranged terminally in the polymer B.

In a further embodiment of the present invention, the polymer B contains terephthalone units which are arranged terminally or in the polymer chain of the polymer B.

In a further embodiment of the present invention, the polymer B contains both isobutene units and terelactone units.

The preparation process may preferably be carried out such that the (meth) acrylic acid copolymer has sulfonate groups with a counterion selected from the group consisting of protons, alkali ions or ammonium ions. However, in general, the sulfonate moieties of the (meth) acrylic acid copolymers can be saturated with any counterion.

The polymers A and B obtainable according to process step (1) are preferably obtained in a polymer solution which has a solids content of preferably 10 to 70%, particularly preferably 30 to 60%, in particular 40 to 55%.

In a particular embodiment of the preparation process, prior to the amidation of the polymers A and B in process step (2), the polymer solution containing the polymer A and B is at a pH of preferably from 2.0 to 9.0, particularly preferably 4.0 adjusted to 7.5, in particular 4.5 to 6.5. In principle, all bases are suitable for this purpose, but preferably aqueous solutions of alkali metal hydroxides, for example aqueous sodium hydroxide solution, are used.

The amidation (process step (2)) is preferably carried out under a protective gas atmosphere, for example using argon or nitrogen. The process step (2) of the preparation process is preferably carried out at temperatures of 140 to 250 ⁰ C, more preferably 165 to 200 ⁰ C, in particular 175 to 185 ° C, performed. The molar ratio of monomer units in polymer A and B to aminoalkanesulfonic acid is preferably 15 to 1 to 2 to 1, more preferably 11 to 1 to 3 to 1, in particular 8 to 1 to 4 to 1. The pressure in process step (2) is preferably 1 to 25 bar, more preferably 5 to 17 bar, in particular 7 to 13 bar.

The (meth) acrylic acid copolymer resulting from process step (1) preferably has at least one of the following structural units based on isopropanol:

The (meth) acrylic acid copolymer obtainable according to the preparation process particularly preferably has isobutene units and / or terelactone units. The isobutene units are preferably arranged terminally in the (meth) acrylic acid copolymer, while the terelactone units can be present both terminally and in the polymer chain.

The formation of these different structural units can generally be carried out according to the following Reaction Scheme (IV):

(IV) The (meth) acrylic acid copolymer B obtainable by the present invention preferably has a weight-average molecular weight of 500 to 20,000 g / mol, more preferably 1,000 to 15,000 g / mol, especially 1,500 to 10,000 g / mol. The weight-average molecular weight is determined by gel permeation chromatography (= GPC) at room temperature with aqueous eluents.

In a particular embodiment of the process according to the invention, aminoethylsulfonic acid is used as the aminoalkylsulfonic acid, so that the polymer resulting from process step (2) has units based on aminoethylsulfonic acid. However, any other aminoalkylsulfonic acids can also be used. In this regard, reference is made to the above statements.

The copolymers (b) are known, for example, from DE-05 3 730 885. They are obtained by copolymerizing the monomers of group (i) with the monomers of group (ii) at temperatures of 80 to 300 ⁰ C by a mass. Suitable monoolefins having 3 to 40 carbon atoms are, for example, 2-propene, isobutene, n-octene-1,2,4,4-trimethylpentene-1,2,4,4-trimethylpentene-2,2-diisobutene, which is technically a mixture of isomers about 80% by weight of 2,4,4-trimethylpentene-1 and about 20% by weight of 2,4,4-trimethylpentene-2, 4,4-dimethylhexene-1, decene-1, dodecene-1 , Tetradecene-1, hexadecene-1, octadecene-1, C ₂ o-olefin-1, C ₂₂ -olefin-1, C ₂₄ -olefin-1, C ₂₀ - to C ₂₄ -olefin-1, C ₂₄ - to C ₂₈ -olefin-1, C ₃₀ -olefin-1, C ₃₅ -olefin-1 and C ₄₀ olefin -1. The olefins or mixtures of olefins are commercial products. Besides the straight-chain olefins, cyclic olefins such as cyclooctene are also suitable. The olefins may contain minor amounts of inert organic hydrocarbons, eg, up to about 5% by weight, as produced. The olefins are commonly used in the commercial grade. You do not need to be subjected to any special cleaning. The preferred olefins are alpha-olefins having chain lengths between C 4 and C 24, as component (ii) of the copolymers are monoethylenically unsaturated C ₄ - to C ₈ - dicarboxylic into consideration, for example, maleic anhydride, itaconic anhydride, methyl saconsäureanhydrid, citraconic anhydride, methylenemalonic and mixtures with each other. Of the anhydrides mentioned, maleic anhydride is preferably used. The copolymers contain from 40 to 60 mol% monoolefins and 60 to 40 mol% of said dicarboxylic anhydrides copolymerized and have a molecular weight of 500 to 20,000, preferably 800 to 12,000 g / mol. They are obtainable by polymerizing the monomers (i) and (ii) in a molar ratio of 1.1: 1 to 1: 1. Preferably, the monomers (i) and (ii) are polymerized in a molar ratio of 1: 1 or use only a 1 wt .-% excess of monomers of component (i). The fashion As is known, the monomers of groups (i) and (ii) form alternating copolymers which contain the monomers (i) and (ii) in copolymerized form at 50 mol% in each case at high molecular weights. At very low molecular weights of the copolymers, depending on the nature of the end groups, there may be a deviation from the molar ratio in the frame indicated above, for example if the copolymer chain starts with the monomer (i) and also terminates with the monomer (i).

The bulk polymerization is carried out at temperatures of 80 to 300, preferably from 120 to 200 ⁰ C, wherein the lowest to be selected polymerization temperature is preferably at least about 20 ⁰ C above the glass transition temperature of the polymer formed. Depending on the molecular weight which the copolymers are to have, the polymerization conditions are selected. Polymerization at high temperatures gives copolymers with low molecular weights, while at lower polymerization temperatures polymers with higher molecular weights are formed. The amount of the polymerization initiator also has an influence on the molecular weight. It generally requires from 0.01 to 5 wt .-%, based on the monomers used in the polymerization, of radical-forming polymerization initiators. Higher amounts of initiator lead to copolymers with lower molecular weights. The monomers (i) and (ii) can also be copolymerized at temperatures above 200 ° C., even in the absence of polymerization initiators, ie it is not absolutely necessary to use initiators because the monomers (i) and (ii) are at temperatures above 200 ° C radically polymerize even in the absence of initiators. Suitable polymerization initiators are, for example, di-tertiary-butyl peroxide, acetylcyclohexanesulfonyl peroxide, diacetyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, tertiary butyl pheodecanoate, 2,2 "azobis (4-methoxy-2,4-dimethylvaleronitrile), tertiary butyl perpivalate, tertiary butylper-2-ethyl-hexanoate, tertiary-butylpermaleinate, 2,2 "-azobis (isobutyronitrile), bis (tertiary-butylperoxy) cyclohexane, tertiary-butylperoxy-isopropylcarbonate, tertiary-butyl-peracetate, di-tertiary-butylperoxide, di-tertiary-amylperoxide, cumene-hydroperoxide and tertiary butyl hydroperoxide. The initiators can be used alone or mixed with each other. In the bulk polymerization, they are preferably introduced into the polymerization reactor separately or in the form of a solution or dispersion in the monoolefin. Of course, redox coinitiators may also be used in the copolymerization, for example benzoin, dimethylaniline, ascorbic acid and organically soluble complexes of heavy metals, such as copper, cobalt, iron, manganese, nickel and chromium. The concomitant use of redox coinitiators makes it possible to carry out the polymerization at a lower temperature. The amounts of redox coinitiators commonly used are about 0.1 to 2000, preferably 0.1 to 1000 ppm, based on the amounts of monomers used. If the monomer mixture is polymerized at the lower limit of the temperature range to be used for the polymerization and then polymerized at a higher temperature, it is expedient to use at least two different initiators which decompose at different temperatures, so that one at each temperature interval sufficient concentration of radicals is available.

In order to prepare low molecular weight polymers, it is often expedient to carry out the copolymerization in the presence of regulators. Conventional regulators can be used for this purpose, for example C 1 - to C ₄ -aldehydes, formic acid and compounds containing organic SH groups, such as 2-mercaptoethanol, 2-mercaptopropanol, mercaptoacetic acid, mercaptopropionic acid, tert-butylmercaptan, n-dodecylmercaptan and tertiary-dodecylmercaptan , The polymerization regulators are generally used in amounts of from 0.1 to 10% by weight, based on the monomers.

The copolymerization is carried out in customary polymerization apparatuses, for example a pressure-tight vessel provided with a stirrer, in pressure-tight stirred tank cascades or in a tubular reactor. In the bulk polymerization, the copolymerization of the olefins and the anhydrides takes place in a molar ratio in the absence of solvents. The copolymerization can be carried out continuously or batchwise. For example, the olefin or a mixture of different olefins can be initially charged in the reactor and heated to the desired polymerization temperature with stirring. As soon as the olefin has reached the polymerization temperature, the ethylenically unsaturated dicarboxylic acid anhydride is metered in. If an initiator is used, it is added to the reaction mixture, preferably separately or dissolved in an olefin coming to polymerization. The polymerization is, if it is used, either separately or dissolved in an olefin dissolved added to the polymerizing mixture. The acid anhydrides, in particular maleic anhydride, are preferably added to the reaction mixture in the form of a melt. The temperature of the melt is about 70 to 90 ° C. If the olefin is used in excess in the copolymerization, for example in a 10% excess, it may without difficulty from the reaction mixture with the aid of a distillation after completion of the copolymerization, preferably under reduced pressure, be removed from the copolymer melt. The copolymerisatschmelze is then conveniently further processed directly. The copolymers thus prepared, after cooling to room temperature or preferably in the form of the melt, which has a temperature in the range of 80 to 180 ⁰ C, preferably 90 to 150 ⁰ C, solvolysiert. The solvolysis of the anhydride groups of the copolymers consists in the simplest case in a hydrolysis and subsequent neutralization. It is particularly advantageous to work in pressure-tight apparatuses and to directly convert the anhydride groups into carboxyl groups by addition of water to a melt of the copolymers obtainable in the bulk polymerization and to neutralize by subsequent addition of bases at least 10% of the carboxyl groups of the hydrolyzed copolymers. However, hydrolysis and neutralization can also be carried out virtually simultaneously by adding dilute aqueous bases to the copolymer melt. The amounts of water and of neutralizing agent are chosen so that 10 to 60, preferably 20 to 55 wt .-% solids containing dispersions or solutions are produced, which are sold. From this, preparation solutions are prepared by dilution to solids contents of 0.5 to 50 wt .-%.

The copolymers obtainable by bulk polymerization can also be solvolyzed by the addition of primary and / or secondary amines. The solvolysis is carried out with such amounts of amines that 10 to 50% of the copolymerized from the copolymerized monomers (ii) in total resulting in a complete hydrolysis carboxyl groups are amidated. After the formation of half-amide groups in the copolymer, the neutralization takes place. It is carried out so far that at least 10% of the carboxyl groups of the copolymer obtained in the bulk polymerization are neutralized. Furthermore, it is also possible to solvolyser with aminocarboxylic acids and salts of aminocarboxylic acids, preferably the alkali metal salts. Particular preference is given to using alkali metal salts of α-aminocarboxylic acids, the alkali metal salts of sarcosine being very particularly advantageous. The solvolysis by means of salts of aminocarboxylic acids is expediently carried out in an aqueous medium. The solvolysis is carried out with such amounts of aminocarboxylates that 10 to 50% of the polymerized from the copolymerized monomers (ii) in total in a complete hydrolysis

Carboxyl groups are amidated. After the formation of half-amide groups in the copolymer, the neutralization takes place. It is carried out to the extent that at least 10% of the carboxyl groups of the copolymer obtained in the bulk polymerization are neutralized.

The solvolysis can also be carried out by adding alcohols to a melt of the copolymers obtainable in the bulk polymerization. You bet with it such amounts of alcohol that 10 to 50% of the total of the polymerized dicarboxylic acid units resulting carboxyl groups are esterified. Subsequently, a neutralization is carried out in which at least 10% of the total resulting from the anhydride-containing copolymer carboxyl groups are neutralized.

Preferably, in each case 25 to 50% of the total of the copolymerized dicarboxylic acid anhydrides resulting carboxyl groups are amidated or esterified. Suitable neutralizing agents are, for example, ammonia, amines, alkali metal and alkaline earth metal bases, for example sodium hydroxide solution, potassium hydroxide solution, magnesium hydroxide, calcium hydroxide, barium hydroxide and all amines which are also used for amidation of the copolymers. The neutralization is preferably carried out by adding aqueous sodium hydroxide solution to the copolymer. The neutralization of the anhydride-containing copolymers is carried out at least to such an extent that water-dispersible copolymers are obtained. This degree of neutralization is at least 10% of the carboxyl groups formed in total from the anhydride groups. The degree of neutralization is also dependent on the chain length of the particular olefin used in component (a). In order to obtain readily water-dispersible or colloidally soluble Copolymorisate, a copolymer of a C ₃₀ olefin and maleic anhydride is neutralized to at least 75%, while, for example, a copolymer of a C _2o / C ₂₄ - olefin and maleic anhydride at a _{degree of} neutralization of 50 % of the carboxyl groups formed from this copolymer are already readily dispersible in water. In a copolymer of a C ₂ -OIeHn maleic anhydride and a degree of neutralization of 20% of the resulting carboxyl groups from the copolymerized maleic anhydride for dispersing the copolymer in water is already sufficient.

For amide formation can be used ammonia and primary and secondary amines. The amide formation is preferably carried out in the absence of water by reaction of the anhydride groups of the copolymer with ammonia or the amines. The suitable primary and secondary amines may have 1 to 40, preferably 3 to 30, carbon atoms. Suitable amines are, for example, methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, hexylamine, cyclohexylamine, methylcyclohexylamine, 2-ethylhexylamine, n-octylamine, isotridecylamine, tallow fatty amine, stearylamine, oleylamine, dimethylamine, Diethylamine, di-n-propylamine, di-isopropylamine, di-n-butylamine, di-isobutylamine, dihexylamine, di-cyclohexylamine, di-methylcyclohexylamine, di-2-ethylhexylamine, di-n-octylamine, di-isotridecylamine, di-n-butylamine. Tallow fatty amine, di-stearylamine, di-oleylamine, ethanolamine, di-ethanolamine, n-propanolamine, di-n-propanolamine and morphine-Nn. Preferably, morpholine is used. In order to partially esterify the copolymers having anhydride groups obtained in the bulk polymerization, they are reacted with alcohols. The esterification is preferably carried out with exclusion of water. Suitable alcohols may contain 1 to 40, preferably 3 to 30, carbon atoms. Primary, secondary and tertiary alcohols can be used. It is possible to use both saturated aliphatic alcohols and unsaturated alcohols, such as oleyl alcohol. Preference is given to using monohydric, primary or secondary alcohols, for example methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, n-pentanol and isomers, n-hexanol and isomers, n-octanol and isomers, for example 2 -Ethylhexanol, nonanols, decanols, dodecano-Ie, tridocanols, cyclohexanol, tallow fatty alcohol, stearyl alcohol and the technically readily accessible by oxo synthesis alcohols or alcohol mixtures having 9 to 19 carbon atoms, such as c _{9 /} n-oxoalcohol, Ci _{2 /} i ₅ -oxoalcohol and Ziegleralkohole, which are known under the name Alfol with 12 to 24 carbon atoms. Are preferably used alcohols having 4 to 24 carbon atoms, such as n-butanol, isobutene Tanol, amyl alcohol, 2-ethylhexanol, tridecanol, tallow fatty alcohol, stearyl alcohol, _{C9 /} n- oxo, Ci _{2 /} i ₅ oxo alcohol, C _{2 /} i ₄ -alpha and Ci _{6 /} i ₈ -alpha.

After the partial conversion of the anhydride groups into half-amide or half-ester groups, the hydrolysis of the remaining anhydride groups of the copolymer is carried out. The hydrolysis of the remaining anhydride groups of the copolymer can also be carried out simultaneously with the still required partial neutralization by adding an aqueous base to the partially amidated or esterified and still containing anhydride copolymer. The amount of water and bases is chosen so that the concentration of the copolymer dispersion or solution is preferably from 20 to 55% by weight. The pH of the ready-to-use agents is in the range of about 4 to 10.

By ceramic masses is meant, for example, building ceramics, such as clay and clay tiles, for masonry and roof (clay bricks, clay roof tiles).

In a simple manner, the additive to be used according to the invention may be added in the form of its aqueous solution shortly before or during extrusion (injection in the extruder) in the course of the production process for the ceramic masses. It is added in amounts of 0.01% to 5%, preferably 0.1 to 1%, based on the solids content of the clay. The additives according to the invention can also be used in combination with other additives suitable for reducing the water content, for example tannins or tannin derivatives, as described in WO 01/09058.

The percentages in the examples are by weight unless otherwise specified. The molecular weights of the copolymers were determined by gel permeation chromatography using tetrahydrofuran as eluant and narrow fractions of polystyrene for calibration.

Examples:

Example 1 :

In a 2 l glass reactor with anchor stirrer, nitrogen inlet, internal thermometer, reflux condenser and dropping funnels you put 400.00 g of 2,4,4-trimethyl-1-pentene (α-diisobutylene) and 2.33 g Lutonal A50 ^® ( Protective colloid). While purging with nitrogen, the initial charge is heated to 103.degree. The following feeds are prepared:

Feed 1: 186.70 g of maleic anhydride (as a melt in a heatable dropping funnel) Feed 2: 9.40 g of tert-butyl peroctoate dissolved in 70.60 g of 2,4,4-trimethyl-1-pentene

When the reaction temperature is reached, 10% of the total amount is added to the reactor at once with stirring from both feeds and allowed to react for 15 minutes. Subsequently, the remaining amounts of both feeds are added continuously at the same time, namely feed 1 within four hours, feed 2 within five hours. After completion of the addition is allowed to react for 1 h at 103 ⁰ C with continued stirring.

Finally, 933.00 g of water are added to the reaction mixture, the reflux condenser is replaced by a distillation bridge and distilled off non-consumed diisobutylene. During the distillation process, 182.90 g of 50% by weight sodium hydroxide solution are added.

This gives a yellowish, viscous polymer solution having a solids content of 25.2%, a pH of 9.7 and a K value of 44.0.

Example 2:

Sodium salt of a copolymer of isobutene and Methacrγlsäureanhydrid, molecular weight 4000 g / mol, K-value 22, pH = 7 (Sokalan ^® PM 10 I, BASF) Example 3:

1.96 kg of maleic anhydride are placed in a kettle, then the kettle is sealed and rendered inert with nitrogen. Subsequently, 0.13 kg of a 20% solution of Lutonal A ^® (BASF) were added. After heating to 120 ° C., 0.844 kg of isobutene are metered in through feed 1 over a period of 5 hours. At the same time 0.252 kg of C-18 alpha-olefin is added through feed 2 within 3 hours. Via feed 3, 0.0831 kg of butyl peroctoate dissolved in 0.35 kg of oxyethylene are added in parallel within 5.5 hours. It is postpolymerized at 120 ° C for about an hour. It is cooled to 100 ⁰ C, added 3.1 kg of water and then the entire XyIoI exchanged for water by means of a steam distillation via a distillation apparatus. Subsequently, 2.1 kg of 50% sodium hydroxide solution are added. Under vacuum, the residual content of xylene is distilled off. A yellowish solution having a solids content of 39.9% and a K value of 21.5 is obtained.

Example 4

Non-additive sound

Example 5:

In a 2 l reactor 250 g of water and 3.0 g of 50% phosphoric acid are superiors sets under a nitrogen atmosphere to an internal temperature of 100 ⁰ C is heated. At this temperature, 517 g of acrylic acid are fed in at the same time by feed 1 within 4 hours, by feed 2 76.0 g of 7% sodium peroxodisulfate within 4.5 hours and by feed 3 44.5 g of mercaptoethanol within 3.75 hours , Then it is cooled to 80 ° C. Dissolved azobis (2-methypropionamidine) dihydrochloride in water and polymerization 16,25g then for 1 hour - within 30 minutes 0.43 g 2,2 ^'is subsequently feed. 4 Then 570 g of 50% sodium hydroxide solution are fed at 80-95 ° C by feed 5 within about 1 hour. At an internal temperature of 80 ° C then 16 g of hydrogen peroxide solution (50%) are added within 30 minutes and stirred for a further 4 hours.

This gives a colorless polymer solution, pH 7.2 with a solids content of 49% and a K value of 20.

Example 6: In a 2 l reactor, 250 g of water and 3.0 g of 50% phosphorous acid are initially charged under an atmosphere of nitrogen to an internal temperature of 100 ⁰ C. At this temperature, feed 5 simultaneously gives 517 g of acrylic acid within 4 hours, Through feed 2 76.0 g of 7% sodium peroxodisulfate within 4.5 hours and fed by feed 3 44.5 g of mercaptoethanol within 3.75 hours. Then it is cooled to 80 ⁰ C. Dissolved azobis (2-methypropionamidine) dihydrochloride in water and polymerization 16,25g then for 1 hour - within 30 minutes 0.43 g 2,2 ^'is subsequently feed. 4 Then at 80-95 ⁰ C by feed 5 within about 1 hour about 110 g of 50% sodium hydroxide added, so that a pH of 4 is set. At an internal temperature of 80 ⁰ C then 16 g of hydrogen peroxide solution (50%) are added within 30 minutes and stirred for a further 4 hours.

This gives a colorless polymer solution, pH 7.2 with a solids content of 48.5% and a K value of 20.

Example 7: In a 2 l reactor, 200 g of water and 2.7 g of 50% phosphorous acid are initially charged under an atmosphere of nitrogen to an internal temperature of 99 ° C. At this temperature, feed 428 g of acrylic acid within 5 hours, feed 2 61.3 g of 7% strength sodium peroxodisulfate within 5.25 hours and feed 3 54 g of mercaptoethanol are fed in within 4.75 hours simultaneously. The mixture is stirred for 15 minutes at 99 ° C and then cooled to 80 ° C. 0.87 g of 2,2'-azobis (2-methypropionamidine) dihydrochloride dissolved in 15.3 g of water are then added through feed 4 within 30 minutes and then polymerized for 1 hour. Then, at 80-95 ⁰ C, 475 g of 50% sodium hydroxide solution are fed in through the inlet 5 for about 1 hour. At an internal temperature of 80 ° C., 14 g of hydrogen peroxide solution (50% strength) are then added over the course of 30 minutes.

This gives a colorless polymer solution, pH 7.2 with a solids content of 47.3% and a K value of 15.

Example 8:

In a 2 l reactor, 300 g of water and 3.42 g of 50% phosphorous acid are placed under a nitrogen atmosphere heated to an internal temperature of 99 ° C. At this temperature, 571 g of acrylic acid dissolved in 100 g of water within 4 hours at the same time, by feed 2 5.71 g of sodium peroxodisulfate dissolved in 57 g of water within 4.5 hours and by feed 3 28 g of mercaptoethanol within closed by 3.75 hours. Then it is cooled to 80 ⁰ C. Subsequently, by feed 4 dissolved within 30 minutes 0.64 g of ^2,2'-azobis (2-methypropionamidine) dihydrochloride was added in 21g water and polymerization was continued then for 1 hour. Then be fed at 80-95 ⁰ C through feed 5 within about 1 hour 625 g of 50% sodium hydroxide solution. At an internal temperature of 80 ° C then 6 g of hydrogen peroxide solution (50%) are added within 30 minutes and stirred for a further 4 hours.

This gives a colorless polymer solution, pH 7.2 with a solids content of 49% and a K value of 30.

Example 9:

Apparatus: pressure vessel with a volume of 2.5 L, anchor stirrer, 2 separate feeds

The kettle is charged with 48.29 g of deionized water, 344.19 g of isopropanol and 31.16 g of hydrogen peroxide solution (30% strength). The boiler is rendered inert with nitrogen and sealed pressure-tight after pressure equalization. The mixture is heated to (220 rpm) at 120 ⁰ C with stirring. At 110 ⁰ C you start the feeds. Feed 1 consists of 431.00 g of isopropanol and 745.50 g (10.35 mol) of acrylic acid. Feed 2 consists of 47.80 g of hydrogen peroxide solution (30%) and 127.17 g of deionized water. The feeds are fed in separately. Feed 1 within 6 hours and feed 2 within 7 hours. The polymerization temperature is 120 ° C. After the end of the feed 2, the reaction mixture is cooled and drained.

In a 2 L HWS apparatus with anchor stirrer and distillation bridge, the isopropanol is removed by simple distillation. During the distillation, 341.26 g of deionized water are added. Subsequently, the pH is adjusted to 4.5 with 50% sodium hydroxide solution and the product is diluted with a further 500 ml of water.

This gives an aqueous polymer solution having a pH of 4.5, a solids content of 44.3% (2 hours Vakärmtrockenschrankt at 100 ° C). The K value is 20.

Example 10:

In a pressure reactor with stirrer, nitrogen inlet, reflux condenser and metering device, 150.0 g of distilled water and 2.17 g of 85% strength by weight phosphoric acid were heated to an internal temperature of 95 ° C. with introduction of nitrogen and stirring. Then, in four separate feeds, 375.4 g of acrylic acid (99.2 mol%) were continuously added in 4 hours, 63.6 g of a 50% strength by weight solution of ethoxylated allyl alcohol (16.6 mol of EO / mol (0.8 mol%), in 4 h 66.2 g of a 40 wt .-% aqueous sodium bisulfite solution and in 4.25 h a GE mixed with 11.50 g of sodium persulfate and 152.2 g of distilled water. After stirring for one hour at 95 ° C and cooling to 50 ° C was adjusted with 50 wt .-% sodium hydroxide solution in 1.5 h, a pH of 6.7. Then, while maintaining a temperature of 50 to 60 ° C 2.12 g of a 50 wt .-% aqueous hydrogen peroxide solution in 30 min metered. Finally, stirring was continued for 30 min at this temperature.

There was obtained a polymer solution having a solids content of 47.3 wt .-% and a K value of 34.3 (measured at pH 7 in 1 wt .-% aqueous solution at 25 ° C).

Example 11:

First, a polymer is prepared from acrylic acid (process step (a)).

In a nitrogen feed, reflux condenser, and dosing reactor, a mixture of 394 grams of distilled water and 5.6 grams of phosphorous acid (50%) was heated to 95 ° C internal temperature with nitrogen and stirring. Then, in parallel, (1) 936 g of acrylic acid, (2) 280 g of sodium peroxodisulfate solution (10%) and (3) 210 g of a 40% by weight aqueous sodium hydrogensulfite solution were continuously added in 5 hours. After stirring for one hour at 95 ° C, the reaction mixture was cooled to room temperature and adjusted by the addition of 169 g of 50 wt .-% sodium hydroxide solution to a pH of 4.0.

There was obtained a clear polymer solution having a solids content of 54 wt .-% and a K value of 25 (1 wt .-% aqueous solution, 25 ⁰ C).

b) A mixture of 1,000 g of the polymer solution from a) (solids content = 50%) and 130.47 g of taurine (aminoethanesulfonic acid) is filled in a pressure-stable reaction vessel with stirrer, nitrogen inlet, temperature sensor, pressure indicator and venting facility. 110 g of a 50% aqueous sodium hydroxide solution are added to this mixture. The apparatus is purged with nitrogen three times and closed.

Then the mixture is heated with stirring to an internal temperature of 180 ⁰ C. This builds up a pressure of about 10 bar. At this temperature, the mixture is held for 5 hours. Then the mixture is cooled without relaxation. The apparatus is opened and adjusted to a pH of 7.2. It becomes a clear yellow solution with a solids content of 49.6% and a K value of

14.6 (1% in 3% NaCl solution). Example 12:

In a 10 l pressure reactor 790.11 g of water, 922.85 g of maleic anhydride, 4.6 mg of iron sulfate (FeSO ₄ x 7 H ₂ O) and 12.78 g of 50% phosphorous acid are placed under an atmosphere of nitrogen to an internal temperature of Heated to 130 ° C. At this temperature, 1117.86 g of acrylic acid dissolved in 788.93 g of water are fed in at the same time by feed 1 within 4.5 hours and by feed 2 309.43 g of hydrogen peroxide solution (50% strength) within 6 hours. The mixture is then polymerized at an internal temperature of 125 ° C for 1.5 hours. Then it is cooled to 80 ° C. Then 11.57 g of hydrogen peroxide solution (50% strength) and 50 g of water are added through feed 3 within 15 minutes and then polymerized for 3 hours.

This gives a colorless polymer solution, pH 1.5 with a solids content of 50% and a K value of 20.

The K values of the polymers were determined according to H. Fikentscher, Cellulose-Chemie, Vol. 13, 48-64 and 71-74 (1932) in aqueous solution at a pH of 7, a temperature of 25 ° C. and a polymer concentration of Sodium salt of the polymers of 1 wt .-% determined.

Test with clay sample preparation

For mixing the test substances, a mixer with mixing blade according to DIN / EN 196 was used. The mixing process was carried out according to the method presented in DIN / EN 196 as follows:

Mixing water (400 ml), flow agents and defoamers were presented. 1 kg of clay (Claytec) was added and stirred at low speed for 90 seconds. The mixture was then allowed to rest for 90 seconds before being stirred again at high speed for 60 seconds. The sample was placed in the measuring vessel. To prevent trapped air, the measuring pot was briefly shocked (3 strokes) by hand and then introduced into the measuring device and fixed. A total of 5:15 minutes after the start of the mix, the measurement was started by the software. Measurement:

For the measurements a rheometer of the type UDS200 of the company Paar Physika was used. As test specimen, the ball measuring system with the designation KMS-2 was used.

Performed were shear rate related measurements, i. the viscosity was determined as a function of the shear rate γ. The selected measurement profile is shown in Table 1 in the overview.

Since the ball leaves an immersion channel when immersed in the sample, a short section (section 1) has been inserted, which moves the ball away from the point of immersion. After that, a break (Section 2) was introduced, which proved to be useful in restoring structures that may have been destroyed by immersion and movement in Section 1.

As comparative examples: D3 Brick, Humin products

All products were measured in concentrations of 0.025%, 0.05, 0.1, 0.15% and 0.2%.

The results are shown in the following table:

Viscosities in Pa s

* Mass polymer (solid) based on mass dry clay ** Fa. Humintech GMbH Dusseldorf *** Fa. Chevron Phillips Chemical Company LP

Application tests with clay

The clay used for the experiments shown below comes from a mine

St. Geours de Maremne in France.

For the extrusion experiments, a laboratory extruder PZVMR 8d Fa. Handle, Mühlacker, Germany was used.

In each case 5000 g of clay in the kneader were first mixed with the polymers, so that the polymer content was 0.2 wt .-% based on the dry content of the clay. In addition, the addition of water in the kneader set a water content of 20.0%. The mixing time per batch was about 10 minutes. The moisture was determined by IR spectroscopy using a Sartorius MA 30 at 130 ° C with automatic shutdown.

As a measure of the plasticity, the torque of the extruder shaft and the radial pressure at the extruder head (mouthpiece) were determined. The lower the torque and the pressing pressure, the higher the plasticity of the additoned clay.

It is surprisingly found that the addition of Homopoyacrylaten (Example 5 to 8) having a molecular weight between 1200 and 8000 g / mol causes a significant reduction of the extruder torque and the pressing pressure compared to non-additiertem clay (Example 4). Thus, the plasticity of the clay has been significantly increased by the polymer addition.

Surprisingly, due to the polymer addition, the flexural strength (BZF) of the dried clay increased significantly, although the water content was identical.

The copolymers also cause an increase in plasticity. As well as an increase in the BZF.

AS = acrylic acid; MSA = maleic anhydride; DIB = diisobutene; IB = isobutene

Determination of bending tensile strength (BZF) The BZF was determined on test bars measuring 20 mm x 15 mm x 120 mm. The samples were dried after extrusion with vacuum for about 72 hours and then at 110 ° C in a drying oven. The measurement was then carried out with a TONI ITECH NI K tester according to the 3-point bending method.

The addition of polyacrylates to the clay allows processing by means of extruders for the production of moldings even at reduced water content. By comparison, the non-polymer additivated clay sample could no longer be processed in the extruder at a moisture content of less than 19.4%. The results are shown below. The polyacrylates were additized in the respective experiment with 0.2 wt .-% based on the dry content of the clay.

Claims

claims

1. Use of

(a) (meth) acrylic acid copolymers containing

(I) 50 to 100 wt .-%, of a poly (meth) acrylic acid skeleton and (ii) 0-40 wt .-%, at least one unit attached to the skeleton and / or incorporated into the skeleton unit selected from the group consisting of isobutene units, terelactone units and isopropanol units and

(Iii) 0 to 50 wt .-%, of units containing sulfonic acid groups (iv) and optionally further units which can be derived from ethylenically unsaturated monomers, wherein the total weight of units in the (meth) acrylic acid copolymer is 100 wt .-% or

(b) Copolymers of

(i) C ₃ -C ₄₀ monoolefins having

(ii) ethylenically unsaturated (XpCe-dicarboxylic anhydrides

as additives in ceramic compositions.

2. Use according to claim 1, characterized in that the ceramic compositions mean clay or clay.

3. Use according to claim 1 or 2, characterized in that the additive is added in amounts of 0.01 to 5 wt .-%.

4. Use according to one of claims 1 to 3, characterized in that the molecular weight of the polymers (a) is 500 to 100,000.

5. Use according to one of claims 1 to 3, characterized in that the molecular weight of the polymers (b) is 500 to 20,000.

6. Use according to one of claims 1 to 4, characterized in that homopolyacrylates are used.

7. Use according to one of claims 1 to 6, characterized in that the ceramic masses are clay or clay roof or bricks.

8. containing ceramic compositions

(a) (meth) acrylic acid copolymers containing

(I) 50 to 100 wt .-%, of a poly (meth) acrylic acid skeleton and (ii) 0-40 wt .-% of at least one unit bonded to the skeleton and / or incorporated into the skeleton unit selected from the group from isobutene units, terelactone units and isopropanol units and

(iii) 0 to 50% by weight of amide units based on aminoalkylsulfonic acids, (iv) and, if appropriate, further units which can be derived from ethylenically unsaturated monomers,

wherein the total weight of the units in the (meth) acrylic acid copolymer is 100% by weight or of

(b) copolymers of (i) C ₃ -C ₄₀ monoolefins with

(ii) ethylenically unsaturated C ₄ -C ₆ dicarboxylic acid anhydrides.

9. containing masonry or roof tiles

(a) (meth) acrylic acid copolymers containing

(Iii) 0 to 50 wt .-% of amide units based on aminoalkylsulfonic acids, (iv) and optionally other units which can be derived from ethylenically unsaturated monomers

the total weight of the units in the meth) acrylic acid copolymer being 100

Wt .-% is or of (b) Copolymers of

(i) C ₃ -C ₄ o-monoolefins having

(ii) ethylenically unsaturated CU-Ce dicarboxylic acid anhydrides.

10. wall or roof tile according to claim 9, characterized in that the bricks are clay or mud brick.

11. A process for the preparation of ceramic compositions, characterized in that as additives

(a) (meth) acrylic acid copolymers containing

(I) 50 to 100 wt .-% of a poly (meth) acrylic acid skeleton and (ii) 0-40 wt .-% of at least one bound to the skeleton and / or incorporated into the skeleton unit selected from the group consisting of Isobutene units, terelactone units and isopropanol units and

(b) copolymers of (i) C ₃ -C ₄₀ monoolefins with

(ii) ethylenically unsaturated C ₄ -C ₆ dicarboxylic acid anhydrides are added.