SI9300497A - Polymerizates, polymer dispensions and use thereof in hydraulic binders - Google Patents

Abstract

Polymers and aqueous polymer dispersants built up from monomers from the group consisting of unsaturated carboxylic acids, unsaturated carboxylic esters (carboxylates), unsaturated sulphonic acids and unsaturated N-substituted cyclic dicarboximides, and their use as additives for hydraulic binders.

Description

Chemie Linz Gesellschaft m.b.H.

Polymerizates and dispersions of polymers as well as their use in hydraulic binders

The invention relates to polymers and dispersions of carboxylic acid based polymers, carboxylic acid esters, sulfonic acids and cyclic imides, to a process for their preparation as well as to their use as additives to hydraulic binders.

Polymerizates based on butadiene, vinyl acetate, vinyl chloride, vinylidene chloride and acrylic acid esters as additives to hydraulic binders, such as e.g. cement, gypsum or anhydrite are known. In order to create resilient, elastic composites of cement and plastic for coatings, tendons, seals, elastic glenes and adhesives, they preferably use soft polymers with glass transition temperatures (Tg) or. freezing temperatures below 0 ° C.

In DE-OS 15 69 910, for example, described polymers of ethylene unsaturated compounds as binders in putty and sealants. These are mixtures of emulsion polymerizates from unsaturated carboxylic acid esters, butadiene, isoprene, isobutene, vinylalkyl ethers, the Tg of which is each time below -5 ° C. DE-OS 25 24 064 discloses aqueous dispersions of copolymerizates with a Tg of -15 to -75 ° C consisting of at least one acrylic or methacrylic acid ester, vinyl acetate, not more than 1.5% by weight of 2-acrylamido-2methylpropanesulfonic acid, and further monomers such as acrylonitrile, styrene and vinyl chloride. These dispersions of plastics are used as adhesives in self-adhesive (pressure sensitive) adhesive tapes that adhere well to resin surfaces, paper and metal. The downside of these dispersions is, above all, their poor compatibility with cement.

DE-OS 32 20 384 describes aqueous dispersions of plastics based on a copolymer of olefinically unsaturated monomers, monomers containing amide groups and unsaturated sulfonic acids in which the sulfo group is attached to acrylic acid or methacrylic acid either via an ester group or via an amide group groups. Particularly suitable monomers are 2-ethylhexyl acrylate as a plasticizing base monomer as well as acrylonitrile, methyl methacrylate or styrene as solid comonomers. They are compatible with cement and exhibit good mechanical properties in connection with cement, such as. tensile strength and elongation. However, the resilience of polymer films to water and the durability of hardened cement and plastic building materials after 28 days of alternate air and water storage is unsatisfactory, in particular, their long-term elasticity is not sufficient for most applications.

Dispersions of plastics obtained by the emulsion polymerisation of esters of unsaturated carboxylic acids, styrene or vinyltoluene and olefinically unsaturated sulfonic acid based on acrylic acid or methacrylic acid are known from DE-OS 38 38 294. A particularly suitable combination is 2-ethylhexyl acrylate. and 2-acrylamido-2,2dimethylethanesulfonic acid. The polymers are used in mixtures with cement, sand and other additives for coatings, coating materials for bridging cracks and jointing compounds. However, building masses manufactured in this way show only very little strength.

JP-A 62-108 759 discloses compositions of polymers and cement based on aqueous dispersions of copolymers containing a maleimide derivative bearing a C1- to C4-alkyl, cyclohexyl or most monosubstituted phenyl residue on the nitrogen atom, as well as monomers, such as e.g. 2-ethylhexyl acrylate, n-butyl acrylate, vinylidene chloride, styrene, acrylonitrile, methyl methacrylate, vinyl acetate, ethylene, vinyl chloride, acrylic acid, acrylamide, methacrylamide, combined so that the minimum film formation temperature of the resulting copolymer is 0. N-phenylmaleimide, N-methylphenylmaleimide, N-hydroxyphenylmaleimide, N-methoxyphenylmaleimide, N-benzoic acid maleimide, N-methylmaleimide, N-tert are used as maleimides. butylmaleimide etc. Polymer dispersions are used in the form of mixtures with cement as coatings for coatings on wood, concrete, mortar, slate, steel, aluminum, fibers, glass and plastics. Their downside, however, is that they contain acrylamide or polymerizers. Methacrylamide, which releases ammonia in a highly alkaline cement mixture, leading to extremely unpleasant odors.

From the Patent Abstracts of Japan, Kokai 63-81177 and Kokai 63-117056, polymerizers are known from unsaturated carboxylic acids, alkyl (meth) acrylates and N-substituted maleimides, which are used to prevent algae, respectively. together with halogenated fos3 fory compounds as non-flammable plastics.

It was an object of the invention to provide polymerizates or. their dispersions based on elastic copolymers having no disadvantages. Such copolymers have been obtained according to the invention by copolymerizing various unsaturated monomers based on carboxylic acids, carboxylic acid esters, sulfonic acids and cyclic imides.

It is therefore an object of the invention to provide polymerisates obtained by polymerisation

a) 70 to 98% by weight of esters of a, β-mono-ethylene-unsaturated carboxylic acids and Cl to C12-alcohols or mixtures of such esters,

b) 0.05 to 15% by weight of N-substituted cyclic imides of α, β-mono-ethylene unsaturated dicarboxylic acids,

c) 0.05 to 5% by weight of α, / 3-mono-ethylene unsaturated carboxylic acids,

d) 0 to 28% by weight of further copolymerizable monomers; and

e) 0.05 to 1% by weight of olefinically unsaturated sulfonic acids.

The polymerizates are preferably formed from

a) 85 to 96% by weight of esters of α, β-mono-ethylene unsaturated carboxylic acids and Cl to C12-alcohols or mixtures of such esters,

b) 0.5 to 7.5% by weight of N-substituted cyclic imides of α, β-mono-ethylene unsaturated dicarboxylic acids,

c) 0.25 to 2.0% by weight of α, β-mono-ethylene unsaturated carboxylic acids,

d) 0 to 13% by weight of further copolymerizable monomers; and

e) 0.25 to 0.75% by weight of olefinically unsaturated sulfonic acids.

A further object of the invention is aqueous dispersions of polymers in which the polymerizates of the invention are dispersed in an aqueous medium which may optionally contain dispersants, emulsifiers, protective colloids as well as further conventional additives. The dispersions of the polymers show solids content preferably of about 40 to 75% by weight, especially preferably 50 to 70% by weight.

The selection of the monomers as well as their mass distribution is preferably carried out in such a way that the mixed polymerizate exhibits a glass transition temperature of not more than 0 ° C, preferably not more than -20 ° C, in order to give the compositions of the hydraulic binders formulated therein high elasticity even at very low temperatures. According to T. G. FOX (Buli. Am. Phys. Soc. Ser. II, 1, 1956, p. 123), the glass transition temperature of mixed polymerizates can be determined by a good approximation from the glass transition temperatures of the individual component homopolymers. To adjust the desired glass transition temperature, we therefore combine the monomers of group a), whose homopolymers show glass transition temperatures typically below 0 ° C, mostly below -40 ° C, with the monomers of groups b) to d) or. e) whose homopolymers have glass transition temperatures typically above + 20 ° C, mostly above + 60 ° C.

As the monomers of group a), olefinically unsaturated mono- or dicarboxylic acids of 3 to 5 carbon atoms are used, preferably in the C1- to C12-alkyl ester. Examples of such esters are ethyl acrylate, n-butyl acrylate, n-hexylacrylate, 2-ethylhexylacrylate, n-dodecylacrylate, 2-ethylhexylmethacrylate, methyl methacrylate, n-butylcrotonate and dibutylfumarate, dioctylfumarate, dibutylaconate, dioctylfumarate, dithylaconate, dioctylfumarate Particularly preferred are 2-ethylhexylacrylate and n-butylacrylate, optionally combined with methyl methacrylate.

As monomers of group b), cyclic imides derived from α, β-mono-ethylene unsaturated dicarboxylic acids, preferably maleic acids, bearing on the imid nitrogen, an alkyl, cycloalkyl or aryl radical which may be optionally substituted are used. Examples of such monomers include N-methylmaleimide, N-ethylmaleimide, N-tert.butylmaleimide, N-cyclohexylmaleimide, N-hydroxyethylmaleimide, N-phenylmaleimide, N-methylphenylmaleimide, N-hydroxyphenylmaleimide, N-hydroxyphenylmaleimide, N-hydroxyphenylmaleimide , 6-dimethylphenyl) -maleimide. Preferred monomers are N-phenylmaleimide and N- (2,6-dimethylphenyl) maleimide.

The monomers of group c) improve in particular the stability of the aqueous dispersions of the polymerizates. These are water-soluble α, β-mono-ethylene unsaturated carboxylic acids, such as e.g.

acrylic acid, crotonic acid, fumaric acid, maleic acid and itaconic acid. Acrylic acid and methacrylic acid are particularly suitable.

In order to optimize the usability of the polymer dispersions, the following monomers are combined (group d), as appropriate. Examples of such monomers are acrylonitrile, styrene, vinyl chloride, vinyl acetate, vinyl propionate, 2-chlorobutadiene as well as di- or trifunctional monomers, such as ethylene glycol triacrylate, divinylbenzene, pentaerythritoltriacryl, triethyleneglycodetriacryl, triethyleneglycolmethacrylate,

Monomers of group e) containing sulfonic acid groups provide, in particular, additional stabilizing effects for the dispersed polymer particles in the preparation and storage of polymer dispersions. In addition, they improve the compatibility of dispersions with cement and thus the homogeneity of the composite of organic and mineral components. Examples of suitable olefinically unsaturated sulfonic acids are 4-styrenesulfonic acid, 3-sulfopropylacrylate, 3-sulfopropylmethacrylate, 2-sulfoethylmethacrylate, 2-sulfoethylmethacrylate, 2-acrylamido-2,2-dimethylethanesulfonic acid, and 2-sulfonidimethylacrylate, and 2-methoxymethylacrylate. Particularly preferred is 2-acrylamido-2,2-dimethylethanesulfonic acid.

Preparation of polymerizates or the dispersion of the polymers of the invention is carried out by polymerization of the monomers in question a) to d) or. e) in an aqueous medium in the presence of radical initiators, dispersants, emulsifiers as well as, where appropriate, regulators and protective colloids. The polymerization can also be carried out both as a batch process and as a feed-in process, and in both cases the polymerization can be stepwise. A feed-forward process is preferred, in which one part of the polymerization attachment is provided, heated to the reaction temperature, and then the monomers in pure or emulsified form are continuously fed from the separate inflows on one side, and the initiator and further auxiliaries, as the case may be, on the other side. for polymerization. The delivery of the monomer is preferably in the form of an aqueous emulsion. After completion of the addition, complete the polymerization by heating at 5 to 10 ° C at a higher temperature, if necessary, cool the reaction mixture to room temperature and adjust it to pH 8 to 9 with the addition of a water-soluble base, preferably alkali hydroxide. between about 20 and 100 ° C, preferably at 40 to 90 ° C. The polymerization temperature is adjusted so that the initiators used are sufficiently rapidly decomposed into the reactive radicals required for metabolism. The multiplicity of radical initiators is about 0.1 to 1 wt.% Based on the total amount of monomer used. Water-soluble inorganic peroxides are particularly suitable, of which peroxodisulphates, such as sodium peroxodisulphate and potassium peroxodisulphate, are particularly preferred. In this case, initiators are used in combination with reducing agents such as formaldehyde disodium sulfoxylate, sodium sulfite, sodium hydrogen sulphite, sodium pyrosulphite, sodium dithionite, sodium thiosulfate and / or ascorbic acid, hydroxylamine. The reducing agent can be further combined with a plurality of heavy metal salts such as ferrous, cobalt, cerium or vanadium salts which act as an accelerator. To supplement the metabolism and to reduce the proportions of the remaining monomers, the subsequent addition of additional amounts of initiates, respectively. combined systems.

In addition to the glass transition temperature and the cross-linking density, the molecular weight of the dispersed polymerizate is the most important molecular influencing amount for decisive technical properties of products such as e.g. stickiness, adhesion, viscoelasticity and tensile strength.

If by changing the polymerization temperature or initiator plurality does not reach the desired molecular weight range, additional molecular weight regulating agents may be used, such as e.g. n-butylmercaptan, tert. butylmercaptan, n-dodecylmercaptan, thioglycol, thioglycolic acid and others in an amount of up to about 2% by weight, calculated on the total amount of monomers used. Preferably, the tert. dodecylmercaptan. Addition of the controller is done arbitrarily, preferably together with monomers.

Anionic, non-ionic or cationic emulsifiers or their compatible mixtures, as is customary in emulsion polymerisation, may be used in the polymerization process of the invention, provided that they are sufficiently soluble in the aqueous phase as well as in the monomer phase and that no interfering interferences occur effects with monomers and other additives. Preferably, anionic surfactants are used as ionic emulsifiers. The emulsifiers prepared by ethoxylation and sulfation of the C _g -C ₁₀ -alkylphenols were particularly effective. For example, from nonylphenol, isononylphenol, isooctylphenol, triisobutylphenol and triteric. butylphenol and carry 3 to 30 units of ethylene oxide. Further examples of possible anionic emulsifiers are alkali metal salts of alkylsulfonic acids, such as e.g. sodium dodecylsulfonate, alkylarylsulfonic acids such as e.g. sodium dodecylbenzenesulfonate as well as ethoxylated and sulfated fatty alcohols with one C _g - C ₂₅ alkyl residue and an ethoxylation rate of 5 to 50, such as e.g. sodium lav7 rylalcholetersulfate with 3 units of EO.

The non-ionic emulsifiers are preferably metabolic products of C _g -C ₁₀ alkylphenols with 3 to 30 moles of ethylene oxide. In addition, ethoxylation products of C ₁₀ -C _{2 ()} -alkanols, such as e.g. lauryl alcohol polyglycol ethers and metabolic products of polypropylene glycol and ethylene oxide.

The desired mean particle size of the dispersed phase can be controlled in a known manner by the type and amount of emulsifiers used, whereby the polymerizate particles become larger, the smaller the amount of emulsifier used. Calculated on the amount of monomer, about 0.2 to 10% by weight, preferably 0.5 to 7% by weight of the emulsifier are used, with particularly advantageous mixtures of anionic, emulsifier and non-ionic emulsifier in a smaller amount.

To prepare anhydrous polymerizates, the polymer dispersions are dried by heating, optionally using a vacuum. Particularly advantageous is spray drying or spray drying. by lyophilization drying.

The polymerizates of the invention, as well as of claims 6 and 8, of monomeric components a) to d) constructed polymerizates, in particular in the form of dispersions of their polymers, are preferably used as additives to hydraulic binders. With hydraulic binders such as cement, lime, gypsum or anhydrite are well compatible and can therefore be advantageously used in building materials that may additionally contain other inorganic and / or organic constituents, such as e.g. sand, gravel, reinforcing fibers. Such building blocks, based on hydraulic binders containing such polymerizates, exhibit increased flexibility. resilience even at very low temperatures and are e.g. usable as materials, grout, sealant, repair, coating, noise protection, topcoat, construction adhesives, intermediate and leveling coatings.

Polymerizates and dispersions of polymers as well as polymerizates and dispersions of polymers based on the monomer components a) to d) of the invention are particularly suitable as binders in compositions containing cement. For the preparation of such compositions we take e.g. an appropriate amount of hydraulic binders, e.g. cement, preferably Portland cement, and optionally pre-mixed with further additives such as sand, man-made fibers, etc. Diluted dispersion of the polymers is then added, optionally with mixed water. However, it is also possible to present anhydrous polymerizates together with hydraulic binders.

One advantage of the products of the invention is, inter alia, that the N-substituted cyclic imide of α, β-mono-ethylene unsaturated dicarboxylic acids, which is present as a comonomic component, is hydrolyzed to the corresponding dicarboxylic acid monoamide under strongly alkaline conditions. resulting in thixotropy of the building material prepared therefrom during its processing. Soft-plastic, fresh, recoverable, non-settling or stirring mixtures are obtained by homogeneously distributing the plastic particles in the mineral matrix. Therefore, it is not necessary to add auxiliary agents for rheology modification, in particular for thixotropy, which often leads to undesirable side effects, such as increased water intake, optionally when the solidified building material swells.

Preferably, the amount of hydraulic binder used is preferably 10 to 150, especially preferably 50 to 100% by weight of the polymerizates of the invention, calculated as a solid resin. This corresponds to the facto plastic - binder 0.1 to 1.5, especially preferably 0.5 to 1.0.

Compositions containing binders based on the polymerizates and dispersions of the polymers of the invention are odorless and are, inter alia, particularly suitable for the manufacture of elastic coatings for bridging cracking, e.g. concrete, where they act, inter alia, as a corrosion protection and as a carbonation inhibitor, as well as in the rehabilitation of buildings, e.g. in the sealing and conservation of facades and roofs. They can further be used for the manufacture of building materials for sound insulation, e.g. for rail tracks to reduce the traffic noise of thymic vehicles.

Example 1

260 g of deionized water were added to a 2.5 liter double walled double walled mixer with mixer, reflux condenser, shielding gas, thermometer and separate connections for the supply vessels and heated to 80 ° C during the nitrogen transfer. To this, 17.5 g was previously added to the stirring vessel in a separate flushing vessel with N ₂ prepared monomer emulsion consisting of:

418.1 g of demineralized water

16.5 g of a 70% aqueous solution of ethoxylated and sulfated nonylphenol (ethoxylation step 4)

27.2 g ethoxylated nonylphenol (ethoxylation rate 10)

25.7 g (2.0 wt%) of methacrylic acid (monomer C)

1.6 g (0.12% by weight) of 2-acrylamido-2,2-dimethylethanesulfonic acid (monomer

E, Lubrizol company)

32.1 g (2.5 wt%) of N-phenylmaleimide (monomer B, Chemie Linz)

1.6 g (0.12 wt%) of triethylene glycol dimethacrylate (monomer D)

1223.4 g (95.26% by weight) of 2-ethylhexylacrylate (monomer A).

When a constant starting temperature of 80 ° C was established, a solution of 6.42 g of sodium persulfate in 64 g of deionized water was brought out of the separate feed vessels for 5 hours and the monomer emulsion residue for 3 hours. After complete addition, polymerization was continued for 2 hours at 80 ° C.

The resulting polymer dispersion was cooled to room temperature and adjusted to pH 8.0 with the addition of 10% aqueous sodium hydroxide. The non-coagulant dispersion had a solids content of about 62.0% by weight. Further data for the resulting polymer dispersion are summarized in Table 2.

Examples 2 to 5:

Analogous to Example 1, polymer dispersion was prepared using the monomers listed in Table 1. The solids content, glass transition temperature, and dynamic viscosity of the resulting polymer dispersions are summarized in Table 2.

Comparative Example VI:

Analogous to Example 1 of DE-OS 32 20 384, a polymer dispersion was prepared based on this monomer composition alone:

27.0 g (2.75 wt%) of methacrylamide

18.0 g (1.83 wt.%) Of 2-acrylamido-2,2-dimethylethanesulfonic acid

900.0 g (91.61% by weight) of 2-ethylhexylacrylate

18.0 g (1.83% by weight) of methacrylic acid

9.0 g (0.92% by weight) of 2-hydroxyethylmethacrylate

1.4 g (0.14 wt%) butanediol- (1,4) dimethacrylate.

The polymer dispersion properties are listed in Table 2.

Table 1: Composition of polymerizates (% by weight)

Monomers *

Example a b c d e 1 95.26 A 2.5 B 2.0 C 0.12 D 0.12 E 2 92.78 A 5.0 B 2.0 C 0.12 D 0.1 E 3 94.88 A 2.5 B 2.0 C 0.12 D 0,5 E 4 80.28 A 15.00 AA 2.5 B 2.0 C 0.12 D 0.1 E 5 95.38 A 2.5 B 2.0 C 0.12 D -

* Monomers used:

A 2-ethylhexylacrylate

AA n-butyl acrylate

B N-phenylmaleimide (Chemie Linz)

C methacrylic acid

D triethylene glycol dimethacrylate

E 2-Acrylamido-2,2-dimethylethanesulfonic acid (Lubrizol company)

Table 2: Properties of polymer dispersion:

Example Solids content ¹ (wt.%) Glass transition temperature ² (° C) Dynamic viscosity (mPa.s) 1 62,0 -55 52 2 59,9 -52 54 3 59.5 -54 135 4 62,2 -53 595 5 61.7 -56 58 VI 62,4 -45 248

determined according to DIN 53 189 according to TGFOX. Buli, Am. Phys. Soc., Ser. II1 (1956), 123 according to DIN 53 019, ISO 3219 at 23 ° C and 250 s ¹

Properties of polymerizates:

1. Water uptake of polymer films

In order to demonstrate the durability of the polymerizates of the invention according to Examples 1 to 5 in comparison with the polymerizate of Comparative Example VI, in particular with regard to their use as a conservation and sealing component in coatings containing binders for the rehabilitation of concrete and buildings, in particular in the outer area, the ability of dispersion films to absorb water. Very high water uptake results in poor weather resistance of the building materials.

Testing was performed according to DIN 53 495 on polymer films with a surface area of 63 cm ² and a layer thickness of 0.6 mm. The polymer films were obtained from 50% by weight diluted dispersions of the polymers, which were poured into molds and dried to constant mass at 40 ° C in a circulating air dryer. After determining their weight, the polymer films were placed in deionized water at 23 ° C for 24 h. Then, by carefully brewing with tissue wipes, we removed the adhering water from them, weighed them, and calculated the weight gain as a percentage. The test results are summarized in Table 3.

2. Shear strength and elongation of materials containing polymerizates

In order to evaluate the mechanical properties of the polymerizates of the invention in comparison with the known polymerizates as constituents of cement-containing building materials for elastic coatings and their durability in the cement composite, the shear strength and elongation were determined in both air-fed, as well as those we kept in the water.

For the manufacture of the test pieces, 50 g of polymer dispersion, diluted to a solids content of 58% by weight, was added to the mix during mixing with Pg 375 H, Mannersdorf. After stirring at 350 rpm for 2 minutes, the resulting cement mixture with a water / cement (V / C) value of 0.42 and a polymer / cement (P / C) value of 0.58 was poured into rectangular plastic, smoothed and dried 24 hours on air. Elastic test specimens were disassembled and left in the air for 3 days. Subsequently, 2 mm thick specimens were divided, keeping one half to 28 days in air (23 ° C). By the 28th day, the second half was stored alternately in the air or in the air. in water with a rhythm of 12 h (water hardness: 6 ° dH). After drying the test specimens kept in water for 24 hours at 23 ° C in air, the test specimens of both test specimens were fed differently. In this case, shear strength and / or shear strength were determined as a criterion for the strength of the composites of cement and polymerizate against dynamic loads. tensile strength depending on elongation or. deformation.

The test was performed with a conventional commercial Rotica plate-to-plate rheometer from Physica (UM-MC 20) at 23 ° C using 5 mm diameter test pieces. The subjects were exposed to oscillating deformative loads at a constant frequency of 0.2 Hz using the MP 5 PP measuring system. The achieved shear strengths against deformation were recorded and converted into elongations, as is known from DIN 53455. The test results are summarized in Table 3.

Comparative measurements show a lower water uptake and thus better weather resistance of the polymerizates of the invention compared to the known polymerizates. Furthermore, compared to cement mixtures containing known polymer additives, cement mixtures containing polymerizates of the invention exhibit better shear strength and elongation, especially after prolonged alternating wet and dry feeding, simulating weathering, and long elasticity or. long lasting agility.

Table 3: Properties of polymerizates and polymerizable cements

Shear Strength Elongation of Polymer Copolymer Cement Cements (%) (Nmm ' ² )

Get up Dry Alternately Dry Edit- H ₂ O poly- warehouse- warehouse- warehouse- čno skla merizat brushing brushing brushing cleaning (wt.%)

1 7.7 0.66 0.47 90 117 2 6,9 1,05 0.84 77 107 3 11,0 0.59 0.48 134 180 4 8.8 0.55 0.82 120 213 5 7.8 0.41 0.61 90 123 VI 56,9 0.37 0.27 44 32 For Chemie Linz Gesellschaft m.b.H .:

PATtrtiHA PISARNA

Claims (8)

PATENT APPLICATIONS Polymerizates, characterized in that they can be obtained by polymerisation a) 70 to 98% by weight of esters of α, β-mono-ethylene unsaturated carboxylic acids and Cl to C12-alcohols or mixtures of such esters, b) 0.05 to 15% by weight of N-substituted cyclic imides of α, β-mono-ethylene unsaturated dicarboxylic acids, c) 0.05 to 5% by weight of α, S-mono-ethylene unsaturated carboxylic acids, d) 0 to 28% by weight of further copolymerizable monomers; and e) 0.05 to 1% by weight of olefinically unsaturated sulfonic acids. Polymerizates according to claim 1, characterized in that they can be obtained by polymerization a) 85 to 96% by weight of esters of α, β-mono-ethylene unsaturated carboxylic acids and Cl to C12-alcohols or mixtures of such esters, b) 0.5 to 7.5% by weight of N-substituted cyclic imides of α, β-mono-ethylene unsaturated dicarboxylic acids, c) 0.25 to 2.0% by weight of α, 3-mono-ethylene unsaturated carboxylic acids, d) 0 to 13% by weight of further copolymerizable monomers; and e) 0.25 to 0.75% by weight of olefinically unsaturated sulfonic acids. Aqueous dispersions of polymers, characterized in that the polymerizates of claim 1 or 2 are dispersed in an aqueous medium. Process for the preparation of polymerizates, characterized in that they are polymerized in an aqueous emulsion a) 70 to 98, preferably 85 to 96% by weight of esters of α, β-mono-ethylene unsaturated carboxylic acids and Cl to C12-alcohols or mixtures of such esters, b) 0.05 to 15, preferably 0.5 to 7.5% by weight of N-substituted cyclic imides of α, β-mono-ethylene unsaturated dicarboxylic acids, c) 0.05 to 5, preferably 0.25 to 2.0% by weight of α, β-mono-ethylene unsaturated carboxylic acids, d) 0 to 28, preferably 0 to 13% by weight of further copolymerizable monomers, and e) 0.05 to 1% by weight, preferably 0.25 to 0.75% by weight of olefinically unsaturated sulfonic acids. Use of aqueous dispersions according to one of claims 1 to 4 as adjuncts to hydraulic binders. 6. Use of aqueous dispersions obtained by polymerisation a) 70 to 98% by weight of esters of α, β-mono-ethylene unsaturated carboxylic acids and Cl to C12-alcohols or mixtures of such esters, b) 0.05 to 15% by weight of N-substituted cyclic imides of α, β-mono-ethylene unsaturated dicarboxylic acids, c) 0.05 to 5% by weight of α, 3-mono-ethylene unsaturated carboxylic acids, d) 0 to 28% by weight of further copolymerizable monomers as additives to hydraulic binders. Hydraulic binders, characterized in that they contain polymerizates according to one of claims 1 to 4. 8. Hydraulic binders, characterized in that they contain polymerizates obtained by polymerisation a) 70 to 98% by weight of esters of a, 3-mono-ethylene-unsaturated carboxylic acids and C1 to C12-alcohols, or mixtures of such esters, b) 0.05 to 15% by weight of N-substituted cyclic imides of α, β-mono-ethylene unsaturated dicarboxylic acids, c) 0.05 to 5% by weight of α, 3-mono-ethylene unsaturated carboxylic acids, d) 0 to 28% by weight of further copolymerizable monomers. For Chemie Linz Gesellschaft m.b.H .: PATENT OFFICE LJUBLJANA 2 23241-viii-93-mn SUMMARY Polymerizates and dispersions of polymers as well as their use in hydraulic binders Polymerizates and aqueous dispersions of polymers made from monomers from the group of unsaturated carboxylic acids, esters of unsaturated carboxylic acids, unsaturated siphonic acids and N-substituted cyclic imides of unsaturated dicarboxylic acids, as well as their use as additives to hydraulic binders.