HK1162040A

HK1162040A - Dispersant containing a copolymer mixture

Info

Publication number: HK1162040A
Application number: HK12102463.0A
Authority: HK
Inventors: Klaus Lorenz; Mario Vierle; Gerhard Albrecht; Barbara Wimmer; Petra Wagner; Christian Scholz
Original assignee: Construction Research & Technology Gmbh
Priority date: 2008-12-08
Filing date: 2009-11-25
Publication date: 2012-08-17

Description

Dispersant containing copolymer mixture

The present invention relates to a polymer composition, a dispersant, the preparation of the polymer composition and the dispersant and the use of the polymer composition.

It is known that admixtures in the form of dispersants are frequently added to aqueous slurries of pulverulent inorganic or organic substances, such as clays, silicate powders, chalk, carbon black, crushed stone and hydraulic binders, for improving their processability, i.e. kneadability, spreadability, sprayability, pumpability or flowability. Such a mixture can prevent the formation of solid agglomerates, and can disperse both the existing particles and the newly formed particles by hydration, thereby improving processability. This effect is used in particular purposefully for the production of building material mixtures containing hydraulic binders, such as cement, lime, gypsum, hemihydrate or anhydrite.

In order to convert building material mixtures based on the binders into ready-to-use, workable form, significantly more mixing water is generally required than is required for the subsequent hydration or hardening process. The mechanical strength and durability are significantly reduced due to the cavity portion formed in the concrete body by the excessive amount of water which is subsequently evaporated.

In order to reduce the excess fraction of water at a defined processing consistency and/or to improve its processability at a defined water/binder ratio, admixtures known as water reducers or superplasticizers are generally used. In particular, copolymers prepared by free-radical copolymerization of acid monomers and/or acid derivative monomers with polyether macromonomers are in practice used as these agents.

WO 2005/075529 describes copolymers which, in addition to acid monomer building blocks, also have ethyleneoxybutylene poly (ethylene glycol) building blocks as polyether macromonomer building blocks. Because of their excellent performance characteristics, such copolymers are widely used as high performance superplasticizers.

Although the described copolymers are considered economical high performance superplasticizers, it is desirable to further improve the quality and cost efficiency of the copolymers.

The object of the present invention was therefore to provide an economical dispersant for hydraulic binders which is particularly suitable as a superplasticizer for concrete.

The object of the invention is achieved by a polymer composition comprising from 3 to 95% by weight of a copolymer H and from 3 to 95% by weight of a copolymer K, the copolymers H and K each having polyether macromonomer structural units and acid monomer structural units which are each present in the copolymers H and K in a molar ratio of from 1: 20 to 1: 1, and at least 20 mol% of all structural units of the copolymer H and at least 25 mol% of all structural units of the copolymer K are each present in the form of acid monomer structural units, the polyether macromonomer structural units of the copolymers H and K having side chains which each contain at least 5 ether oxygen atoms, the number of ether oxygen atoms in each side chain of the polyether macromonomer structural units of the copolymers H and K each varying in the following manner: respective frequency profiles, in which the number of ether oxygen atoms in each side chain of the polyether macromonomer structural units is plotted along the abscissa and the respective frequency of correlation of the copolymers H or K is plotted along the ordinate, each contain at least 2 maxima whose abscissa values differ from one another by more than 7 ether oxygen atoms, the frequency profiles of the copolymers H and K differ from one another in that the abscissa values of at least 1 maximum of the copolymer H and the abscissa values of all maxima of the copolymer K differ from one another by more than 5 ether oxygen atoms, and/or in that the arithmetic mean of the ether oxygen atoms of the polyether macromonomer structural units of the copolymers H and K differ from one another by more than 5 ether oxygen atoms.

The acid monomer building blocks are prepared by incorporating the acid monomer in the form of polymerized units. Acid monomers are understood here to be monomers which are capable of free-radical copolymerization, have at least one carbon double bond, contain at least one acid function and react as an acid in an aqueous medium. In addition, acid monomers are also understood to be monomers which are capable of undergoing free-radical copolymerization, have at least one carbon double bond, form at least one acid function as a result of hydrolysis reactions in aqueous media, and react as an acid in aqueous media (e.g.maleic anhydride or base-hydrolyzed acrylates, such as ethyl acrylate). The polyether macromonomer is formed by introducing the corresponding polyether macromonomer in the form of polymerized units. Therefore, in the present invention, the polyether macromonomer is a compound capable of radical copolymerization, having at least one carbon double bond and having an ether oxygen atom. Thus, the polyether macrobuilding blocks present in the copolymer each have at least one side chain containing an ether oxygen atom.

In general, it can be said that the mode of action of the relevant copolymers having polyether macromonomer building blocks and acid building blocks is determined by their structural parameters. The spectrum of action of the corresponding high performance copolymer covers the entire range from extreme water reduction to extreme slump retention, where the structural parameters that ensure water reduction contradict those that provide good slump retention. Thus, in addition to the loading per unit mass, the length of the side chains is also decisive, for example for the water-reducing capacity. The metering of the relevant superplasticizer copolymers is usually carried out as a percentage by weight of cement of the cementitious mixture, i.e. on a mass basis. In general, the quality of the application and the number of active substance molecules are decisive for the mode of action. However, long side chains have a high mass, as opposed to as large as possible the number of copolymer molecules per unit mass. By introducing short side chains in addition to the long side chains, the molar mass of the copolymer can be reduced without adversely affecting the dispersing effect (this is also due to the long side chains). It is therefore often very suitable to introduce short and long polyether side chains simultaneously into the copolymer molecule, according to the principle of "one each with as few long side chains as possible, which meets the requirements". The copolymer superplasticizer is able to optimize its mass efficiency in this way. This optimization can be used separately for the two extremes of the spectrum of action (water reduction, slump retention). In applications where both water reduction and consistency maintenance are required, a physical mixture of these individually mass optimized superplasticizer copolymers can be advantageously used as compared to a single superplasticizer copolymer optimized for the application. The advantage is a more stable cement quality (alkali and sulphate content), temperature variations, or the mixture can be simply adjusted. Overall, it can be said that the polymer composition according to the invention represents a particularly economical and high-quality dispersant or superplasticizer.

In general, the polymer compositions of the invention contain from 10 to 85% by weight of copolymer H and from 10 to 85% by weight of copolymer K.

Preferably, at least 50 mol% of all structural units of copolymer H and at least 50 mol% of all structural units of copolymer K are each present in the form of acid monomer structural units.

In general, the number of ether oxygen atoms in each side chain of the polyether macromonomer building blocks of copolymers H and K each varies in this way: the frequency distribution diagram of the correlations, in which the number of ether oxygen atoms in each side chain of the polyether macromonomer structural units is plotted along the abscissa and the respective frequency of the correlations of the copolymers H or K is plotted along the ordinate, each contains at least 2 maxima, the abscissa values of which differ from one another by more than 10 ether oxygen atoms each.

Frequently, the number of ether oxygen atoms in each side chain of the polyether macromonomer building blocks of copolymers H and K varies each in this way: a correlation frequency distribution plot, wherein the number of ether oxygen atoms in each side chain of polyether macromonomer building blocks is plotted along the abscissa and the respective correlation frequency of copolymer H or K is plotted along the ordinate, each containing at least 2 maxima, the abscissa values of which differ from one another by more than 10 ether oxygen atoms, the frequency distribution plots of copolymers H and K differing from one another in that the abscissa of at least one maximum of copolymer H differs from the abscissa of all maxima of copolymer K by more than 10 ether oxygen atoms each.

In general, the acid monomer building blocks of the copolymers H and K are each present in one of the general formulae (Ia), (Ib), (Ic) and/or (1d),

wherein

R¹Identical or different and denotes H and/or linear or branched C₁-C₄An alkyl group;

x is the same or different and represents NH- (C)_nH_2n) Wherein n ═ 1, 2, 3 or 4, and/or represents O — (C)_nH_2n) Wherein n ═ 1, 2, 3 or 4, and/or represents absent units;

R²are the same or different and represent OH, SO₃H、PO₃H₂、O-PO₃H₂And/or para-substituted C₆H₄-SO₃H, provided that if X is a non-existent unit, then R²Represents OH;

wherein

R³Identical or different and denotes H and/or linear or branched C₁-C₄An alkyl group;

n is 1, 2, 3 or 4;

R⁴are the same or different and represent SO₃H、PO₃H₂、O-PO₃H₂And/or para-substituted C₆H₄-SO₃H；

(Ic)

Wherein

R⁵Identical or different and denotes H and/or linear or branched C₁-C₄An alkyl group;

z is identical or different and denotes O and/or NH;

wherein

R⁶Identical or different and denotes H and/or linear or branched C₁-C₄An alkyl group;

q is identical or different and denotes NH and/or O;

R⁷are the same or different and represent H; (C)_nH_2n)-SO₃H, wherein n is 0, 1, 2, 3 or 4; (C)_nH_2n) -OH, wherein n ═ 0, 1, 2, 3, or 4; (C)_nH_2n)-PO₃H₂Wherein n is 0, 1, 2, 3 or 4; (C)_nH_2n)-OPO₃H₂Wherein n is 0, 1, 2, 3 or 4; (C)₆H₄)-SO₃H；(C₆H₄)-PO₃H₂；(C₆H₄)-OPO₃H₂(ii) a And/or (C)_mH_2m)_e-O-(A`O)_α-R⁹Wherein m is 0, 1, 2, 3 or 4, e is 0, 1, 2, 3 or 4, a ═ C_x′H_2x′Wherein x' is 2, 3, 4 or 5, and/or CH₂C(C₆H₅) H-, alpha is an integer from 1 to 350, and R⁹Are identical to each otherOr different and represents H and/or C, linear or branched₁-C₄An alkyl group.

Depending on the pH, the acid monomer building block can also be present in deprotonated form as a salt, where the typical counterion is Na⁺、K⁺And Ca²⁺。

Frequently, the acid monomer building blocks of the copolymers H and K are each prepared by incorporating the acid monomers methacrylic acid, acrylic acid, maleic anhydride and/or maleic monoester in the form of polymerized units.

Preferably, the copolymer H and K polyether macromonomer building blocks are each present in one of the general formulae (IIa), (IIb) and/or (IIc),

wherein

R¹⁰、R¹¹And R¹²Each of which is the same or different and independently represents H and/or straight or branched C₁-C₄An alkyl group;

e are identical or different and denote straight-chain or branched C₁-C₆Alkylene, cyclohexyl, CH₂-C₆H₁₀Ortho-, meta-, para-substituted C₆H₄And/or represents an absent element;

g is identical or different and denotes O, NH and/or CO-NH, with the proviso that, if E is a non-existent unit, G also denotes a non-existent unit;

a is the same or different and denotes C_xH_2xWherein x is 2, 3, 4 and/or 5 (preferably x is 2), and/or represents CH₂CH(C₆H₅)；

n is identical or different and denotes 0, 1, 2, 3, 4 and/or 5;

a is the same or different and represents an integer from 5 to 350 (preferably 10-200);

R¹³identical or different and denotes H, straight-chain or branched C₁-C₄Alkyl, CO-NH₂And/or COCH₃；

Wherein

R¹⁴Identical or different and denotes H and/or linear or branched C₁-C₄An alkyl group;

e are identical or different and denote straight-chain or branched C₁-C₆Alkylene, cyclohexyl, CH₂-C₆H₁₀Ortho-, meta-, para-substituted C₆H₄And/or represents a unit that is not present;

g is the same or different and denotes absent units, O, NH and/or CO-NH, with the proviso that if E is absent units, G also denotes absent units;

a is the same or different and denotes C_xH_2xWherein x is 2, 3, 4 and/or 5, and/or represents CH₂CH(C₆H₅)；

n is identical or different and denotes 0, 1, 2, 3, 4 and/or 5;

a is the same or different and represents an integer from 5 to 350;

d is identical or different and denotes one absent unit, NH and/or O, with the proviso that, if D is one absent unit, b is 0, 1, 2, 3 or 4, c is 0, 1, 2, 3 or 4, wherein b + c is 3 or 4, and with the proviso that, if D is NH and/or O, b is 0, 1, 2 or 3, c is 0, 1, 2 or 3, wherein b + c is 2 or 3;

R¹⁵identical or different and denotes H, straight-chain or branched C₁-C₄Alkyl radicals, CO-NH₂And/or COCH₃A chain;

wherein

R¹⁶、R¹⁷And R¹⁸Each of which is the same or different and independently represents H and/or straight or branched C₁-C₄An alkyl group;

e are identical or different and denote straight-chain or branched C₁-C₆Alkylene, cyclohexyl, CH₂-C₆H₁₀And/or ortho-, meta-, para-substituted C₆H₄；

n is identical or different and denotes 0, 1, 2, 3, 4 and/or 5;

l are the same or different and represent C_xH_2xWherein x is 2, 3, 4 and/or 5, and/or represents CH₂CH(C₆H₅)；

a is the same or different and represents an integer from 5 to 350;

d is the same or different and represents an integer from 1 to 350;

R¹⁹identical or different and denotes H and/or linear or branched C₁-C₄An alkyl group;

R²⁰identical or different and denotes H and/or linear or branched C₁-C₄An alkyl group.

Frequently, the polyether macromonomer building blocks of copolymers H and K are each prepared by introducing a polyether macromonomer alkoxylated hydroxybutyl vinyl ether and/or alkoxylated diethylene glycol monovinyl ether and/or alkoxylated isoprene alcohol and/or alkoxylated (meth) allyl alcohol and/or a vinylated methylpolyalkylene glycol, said monomer preferably having an alkylene oxide group in the form of polymerized units with an arithmetic average of from 6 to 300.

The alkoxy units in the polyether macromers are usually present as ethoxy groups or as a mixture of ethoxy and propoxy groups (these polyether macromers are obtained by ethoxylating or ethoxylating and propoxylating the corresponding monomeric alcohols).

The copolymers H and K may each have polyether macromonomer building blocks and/or acid monomer building blocks of the same or different types.

In general, at least 45 mol%, preferably at least 80 mol%, of each of all the structural units of the copolymers H and K are prepared by incorporating the acid monomers and the polyether macromonomers in the form of polymerized units.

The invention also relates to a dispersant comprising at least 30% by weight of water and at least 10% by weight of the above polymer composition. The dispersant is preferably present in the form of an aqueous solution.

The invention furthermore relates to a process for preparing the polymer compositions according to the invention or the dispersants according to the invention, in which the copolymers H and K are prepared separately in aqueous solution and the separately prepared copolymers or the separately prepared aqueous solutions are then mixed with one another.

Generally, the acid monomer and polyether macromonomer are reacted in aqueous solution by free radical polymerization using an aqueous redox initiator system containing a peroxide, the aqueous solution being at a temperature of 10 to 45 ℃ and a pH of 3.5 to 6.5 during the polymerization.

Finally, the invention also relates to the use of the polymer composition according to the invention as a dispersant for hydraulic binders and/or latent hydraulic binders. Typically, the hydraulic binder is present as cement, lime, gypsum, hemihydrate or anhydrite or a mixture of these components, preferably cement. Latent hydraulic binders are usually present as fly ash, volcanic soil, blast furnace slag. The polymer compositions of the invention can also be used, for example (especially in dehydrated form), as additives to cementitious products (as grinding aids and "water reducers" for fine portland cement or blended cements).

The invention will be explained in more detail below with reference to embodiments and with reference to the drawings.

In the drawings:

FIG. 1 is a graph schematically showing the frequency of the number of pendant ether oxygen atoms, which relates to a polymer composition of an example of use of the present invention;

FIG. 2 is a graph showing the change in slump with time in which the polymer composition in the use example of the present invention is compared with other polymer compositions.

Synthesis example 1 copolymer H in a Polymer composition according to the invention

227g of deionized water and 250g of ethyleneoxybutyl polyethylene glycol-1100 (22mol of adduct of ethylene oxide and hydroxybutyl monovinyl ether) and 113.6g of ethyleneoxybutyl polyethylene glycol-500 (9mol of adduct of ethylene oxide and hydroxybutyl monovinyl ether) were initially charged in a glass reactor equipped with a stirrer, a pH electrode and a plurality of feed devices and then cooled to the polymerization initiation temperature of 12 ℃ (initial mixture).

In a separate feed tank, 39.3g of acrylic acid and 29.58g of hydroxypropyl acrylate were mixed uniformly with 206.65g of deionized water. The solution was brought to a temperature of 20 ℃ and a pH of 4.0 using 23.27g of 40% strength potassium hydroxide solution with cooling. Then 2.88g of 3-mercaptopropionic acid was added as molecular weight regulator (solution A).

At the same time, a mixture (B) of 2.07g of disodium 2-hydroxy-2-sulfinatoacetate, disodium 2-hydroxy-2-sulfoacetate and sodium sulfite was preparedrüggolitFF6 from Bruggemann GmbH) and 66.93g of water (solution B).

Then, 89.6g of solution A and subsequently 5.9g of a 20% strength aqueous sodium hydroxide solution and 1.55g of 3-mercaptopropionic acid were added to the initial mixture with stirring and cooling as molecular weight regulators.

Then, 0.085g of iron (II) sulfate heptahydrate and 5.22g of hydrogen peroxide (30% aqueous solution) were added sequentially to the initial mixture, while starting the addition of solution a and solution B to the initial mixture under stirring.

The rate of addition of the remaining solution A is shown in the metering curve below. The addition rate of solution B was 33.5g/h, the addition was 45min and then increased to 205g/h, and the metering was continued until all the solution had entered the reactor. During the reaction, 18g of 20% strength sodium hydroxide solution were added stepwise.

Time (min)	0	1.5	3	6	9	12	15	18	21	24	27	30	33	36	39	45
																	Solution A (g/h)	143	287	502	600	558	502	430	343	272	212	170	127	103	72	63	0

After the addition of solutions A and B was complete, no peroxide was found in the reactor.

The resulting polymer solution was then adjusted to a pH of 6.5 using about 42g of 20% strength sodium hydroxide.

The copolymer obtained was a pale yellow solution with a solids content of 44.3%. The average molecular weight Mw of the copolymer was 24000g/mol, the conversion according to GPC was 95%.

Synthesis of example 2 copolymer K of the Polymer composition according to the invention

423.4g of deionized water and 16.65g of ethyleneoxybutyl polyethylene glycol-1100 (22mol of adduct of ethylene oxide and hydroxybutyl monovinyl ether) and 351.25g of ethyleneoxybutyl polyethylene glycol-5800 (129mol of adduct of ethylene oxide and hydroxybutyl monovinyl ether) were initially charged in a glass reactor equipped with stirrer, pH electrode and a plurality of feed devices and then cooled to the polymerization initiation temperature of 15 ℃ (initial mixture).

In separate feed tanks, 19.64g of acrylic acid and 15.76g of hydroxypropyl acrylate were homogeneously mixed with 106.20g of deionized water. The solution was brought to a temperature of 20 ℃ and a pH of 3.5 using 5.44g of 40% strength potassium hydroxide solution with cooling. Then 2.52g of 3-mercaptopropionic acid were added as molecular weight regulator (solution A).

At the same time, a mixture of 1.68g of the disodium salt of 2-hydroxy-2-sulfinato acetic acid, the disodium salt of 2-hydroxy-2-sulfoacetic acid and sodium sulfite (Brugolit) was preparedFF6 from Bruggemann GmbH) and 26.32g of water (solution B).

Then, 73.5g of solution A and subsequently 11.0g of 20% strength aqueous sodium hydroxide solution and 0.28g of 3-mercaptopropionic acid were added to the initial mixture with stirring and cooling as molecular weight regulators.

0.1488g of iron (II) sulfate heptahydrate and 2.53g of hydrogen peroxide (30% aqueous solution) were then added to the initial mixture, while the addition of solution A and solution B to the initial mixture under stirring was started.

The rate of addition of the remaining solution A is shown in the metering curve below. The addition rate of solution B was 36.9g/h, the addition was 30min and then increased to 89g/h, and the metering was continued until all the solution had entered the reactor. During the reaction, 1.6g of 20% sodium hydroxide solution was added stepwise.

Time (min)	0	2	4	6	8	10	12	14	16	18	22	26	30
														Solution A (g/h)	222	247	257	257	247	222	182	149	119	92	56.9	35	0

The resulting polymer solution was then adjusted to a pH of 6.5 with about 30g of 20% strength sodium hydroxide solution.

The copolymer solution obtained was a pale yellow solution with a solids content of 40.6%. The copolymer has an average molecular weight Mw of 73000g/mol and a conversion by GPC of 87%.

Synthesis example 3 (for comparison-not referring to the Polymer composition of the invention)

Chemical mixture "

Corresponding to 0.7 part of copolymer K and 0.3 part of copolymer H

59.64g of deionized water and 15.95g of vinyloxybutylpolyglycol-1100 (22mol of adduct of ethylene oxide and hydroxybutyl monovinyl ether) and 162.40g of vinyloxybutylpolyglycol-5800 (129mol of adduct of ethylene oxide and hydroxybutyl monovinyl ether) and 3.75g of vinyloxybutylpolyglycol-500 (10mol of adduct of ethylene oxide and hydroxybutyl monovinyl ether) were initially charged in a glass reactor equipped with a stirrer, a pH electrode and a plurality of feed devices and then cooled to the polymerization initiation temperature of 15 ℃ (initial mixture).

In separate feed tanks, 10.38g of acrylic acid and 8.26g of hydroxypropyl acrylate were mixed homogeneously with 67.2g of deionized water. The solution was brought to a temperature of 20 ℃ and a pH of 3.5 (solution A) using 3.05g of a 40% strength potassium hydroxide solution with cooling.

At the same time, a mixture of 3g of disodium 2-hydroxy-2-sulfinato acetate, disodium 2-hydroxy-2-sulfoacetate and sodium sulfite (Bruggolit) was preparedFF6 from Bruggemann GmbH) and 47g of water (solution B).

44.75g of solution A and subsequently 2.6g of 20% strength aqueous sodium hydroxide solution and 0.16g of 3-mercaptopropionic acid were added to the initial mixture with stirring and cooling as molecular weight regulators. 1.44g of 3-mercaptopropionic acid were added to the remaining solution A.

After the pH of the initial mixture reached 5.3, 0.0875g of iron (II) sulfate heptahydrate was added to the initial mixture, followed by 1.49g of hydrogen peroxide (30% aqueous solution). At the same time, the addition of solution a and solution B to the initial mixture under stirring was started.

The rate of addition of the remaining solution A is shown in the metering curve below. The addition rate of solution B was 20.8g/h, the addition was 30min and then increased to 100g/h, and the metering was continued until all the solution had entered the reactor. During the reaction, 3.9g of 20% strength sodium hydroxide solution were added stepwise.

Time (min)	0	2	4	6	8	10	12	14	16	18	22	26	30
														Solution A (g/h)	140	155	162	162	155	140	114	94	75	58	36	22	0

After the addition of solutions A and B was complete, no peroxide was present in the reactor.

The resulting polymer solution was then adjusted to pH6.5 using 15g of 20% strength sodium hydroxide solution.

The copolymer obtained was a pale yellow solution with a solids content of 41.5%. The copolymer has an average molecular weight Mw of 57000g/mol and a conversion, based on GPC, of 89%.

To prepare the polymer composition of the invention ("physical mixture" for the use examples of the invention described below), 129.21g of the polymer solution of copolymer K (Synthesis example 2) were mixed with 50g of the polymer solution of copolymer H (Synthesis example 1) in a corresponding mixing ratio of 70: 30, based on the respective polymer solids of the copolymers H and K. The schematic diagram of FIG. 1 shows the number of ether oxygen atoms in each side chain of the polyether macromonomer building blocks (of all copolymers H and K) in the polymer compositions of the present invention prepared in this way along the abscissa (X-axis) and the respective associated frequencies along the ordinate (Y-axis). The maximum frequency arises when the average number of ether oxygen atoms is 23, since here the frequency of the copolymers H and K, which corresponds to the starting ethyleneoxybutylpolyethylene glycol-1100 (adduct of 22mol of ethylene oxide and hydroxybutyl monovinyl ether) used in both synthesis examples 1 and 2, is additive. The average number 23 is derived taking into account another ether oxygen atom derived from the vinyl "head group" of the macromonomer building block. The same applies to the two other ethyleneoxybutylpolyglycols used. Fig. 1 also shows the spacing of maxima of the respective distributions of the physical mixtures of copolymers H and K. The re-formed distribution of ether oxygen atoms corresponding to a "bell plot" is merely schematic (the actual distribution width may be different).

All polymer mixtures tested in the use examples below were mixed with a small amount of a conventional defoamer to control the air void content.

Use examples:

slump was tested according to DIN 12350-5 on fresh concrete,

400kg of CEM I52.5R Mergelstetten, w/c 0.36, at respective doses of 0.21%

The results of the use examples are shown in the graph of fig. 2, in which the time is plotted in minutes along the abscissa (N), the slump is plotted in cm along the ordinate (M), the circles represent standard superplasticizers (without mixed side chains), the diamonds represent copolymer H as an optimized superplasticizer variant, the triangles represent the inventive physical mixture of copolymers H and K, and the squares represent the mixture according to synthesis example 3.

Copolymer H (diamond icon) as an optimized variant of the standard plasticizer (Glenium ACE 30, from BASF, which does not contain mixed side chains, circle icon) shows a particularly good workability within the first 40 minutes at a corresponding dose of 0.21% (superplasticizer solids, based on the weight of cement in the mixture). In contrast, the physical mixtures of the copolymers H and K of the invention in a mixing ratio of 0.7: 0.3 (based on the polymer content in the solution) show a much more greatly improved performance even up to 60min (triangle icon). The mixture according to synthetic example 3 (square icon) is inferior to the mixture according to the invention (triangle icon), firstly because it leads to a significantly greater post-plasticization (increase in slump from 56 to 63.5 in the first 10 minutes) and secondly because it does not guarantee a better workability over time (slump of 55cm even after 40 minutes, whereas the mixture according to the invention still has a slump of 61cm after 60 minutes).

Claims

1. A polymer composition comprising from 3 to 95% by weight of a copolymer H and from 3 to 95% by weight of a copolymer K, the copolymers H and K each having polyether macromonomer structural units and acid monomer structural units, each present in the copolymers H and K in a molar ratio of from 1: 20 to 1: 1, and at least 20 mol% of all structural units of the copolymer H and at least 25 mol% of all structural units of the copolymer K each present in the form of acid monomer structural units, the polyether macromonomer structural units of the copolymers H and K containing side chains each containing at least 5 ether oxygen atoms, the number of ether oxygen atoms in each side chain of the polyether macromonomer structural units of the copolymers H and K each varying in the following manner: respective frequency profiles, in which the number of ether oxygen atoms in each side chain of the polyether macromonomer structural units is plotted along the abscissa and the respective frequency of correlation of the copolymers H or K is plotted along the ordinate, each contain at least 2 maxima whose abscissa values differ from one another by more than 7 ether oxygen atoms, the frequency profiles of the copolymers H and K differ from one another in that the abscissa values of at least 1 maximum of the copolymer H and the abscissa values of all maxima of the copolymer K differ from one another by more than 5 ether oxygen atoms each and/or in that the arithmetic mean values of the ether oxygen atoms of the polyether macromonomer structural units of the copolymers H and K differ from one another by more than 5 ether oxygen atoms.

2. A polymer composition according to claim 1, comprising from 10 to 85% by weight of copolymer H and from 10 to 85% by weight of copolymer K.

3. Polymer composition according to claim 1 or 2, wherein at least 50 mol% of all structural units of copolymer H and at least 50 mol% of all structural units of copolymer K are each present in the form of acid monomer structural units.

4. A polymer composition according to one of claims 1 to 3, characterized in that the number of ether oxygen atoms in each side chain of the polyether macromonomer building blocks of copolymers H and K varies each in the following manner: the corresponding frequency profiles, in which the number of ether oxygen atoms in each side chain of the polyether macromonomer structural units is plotted along the abscissa and the respective frequency of correlation of the copolymers H or K is plotted along the ordinate, each contain at least 2 maxima whose abscissa values differ from one another by more than 10 ether oxygen atoms each.

5. Polymer composition according to one of claims 1 to 4, characterized in that the number of ether oxygen atoms in each side chain of the polyether macromonomer building blocks of copolymers H and K varies in the following manner: the frequency profiles of the copolymers H and K differ from one another in that the abscissa values of at least 1 maximum of the copolymer H and the abscissa values of all the maxima of the copolymer K differ from one another by more than 10 ether oxygen atoms each.

6. Polymer composition according to one of claims 1 to 5, characterized in that the acid monomer building blocks of the copolymers H and K are each present in one of the general formulae (Ia), (Ib), (Ic) and/or (Id),

wherein

(Ib)

wherein

n is 1, 2, 3 or 4;

Wherein

z is identical or different and denotes O and/or NH;

wherein

q is identical or different and denotes NH and/or O;

R⁷are the same or different and represent H; (C)_nH_2n)-SO₃H, wherein n is 0, 1, 2, 3 or 4; (C)_nH_2n) -OH, wherein n ═ 0, 1, 2, 3, or 4; (C)_nH_2n)-PO₃H₂Wherein n is 0, 1, 2, 3 or 4; (C)_nH_2n)-OPO₃H₂Wherein n is 0, 1, 2, 3 or 4; (C)₆H₄)-SO₃H；(C₆H₄)-PO₃H₂；(C₆H₄)-OPO₃H₂(ii) a And/or (C)_mH_2m)_e-O-(A`O)_α-R⁹Which isWherein m is 0, 1, 2, 3 or 4, e is 0, 1, 2, 3 or 4, a ═ C_x′H_2x′Wherein x' is 2, 3, 4 or 5, and/or CH₂C(C₆H₅) H-, alpha is an integer from 1 to 350, R⁹Identical or different and represent H and/or C, linear or branched₁-C₄An alkyl group.

7. Polymer composition according to one of claims 1 to 6, wherein the acid monomer building blocks of the copolymers H and K are each prepared by introducing the acid monomers methacrylic acid, acrylic acid, maleic anhydride and/or monoesters of maleic acid in the form of polymerized units.

8. Polymer composition according to one of claims 1 to 7, characterized in that the polyether macromonomer building blocks of the copolymers H and K are each present in one of the general formulae (IIa), (IIb) and/or (IIc),

wherein

n is identical or different and denotes 0, 1, 2, 3, 4 and/or 5;

(IIb)

Wherein

n is identical or different and denotes 0, 1, 2, 3, 4 and/or 5;

a is the same or different and represents an integer from 5 to 350;

d is identical or different and denotes one absent unit, NH and/or O, with the proviso that, if D is one absent unit, b is 0, 1, 2, 3 or 4 and c is 0, 1, 2, 3 or 4, wherein b + c is 3 or 4, and with the proviso that, if D is NH and/or O, b is 0, 1, 2 or 3, c is 0, 1, 2 or 3, wherein b + c is 2 or 3;

R¹⁵are the same or different, andand represents H, straight or branched C₁-C₄Alkyl radicals, CO-NH₂And/or COCH₃A chain;

wherein

R¹⁶、R¹⁷And R¹⁸Identical or different and, independently of one another, represent H and/or C, which is linear or branched₁-C₄An alkyl group;

n is identical or different and denotes 0, 1, 2, 3, 4 and/or 5;

a is the same or different and represents an integer from 5 to 350;

d is the same or different and represents an integer from 1 to 350;

9. Polymer composition according to one of claims 1 to 8, characterized in that the polyether macromonomer building blocks of the copolymers H and K are each prepared by incorporating a polyether macromonomer alkoxylated hydroxybutyl vinyl ether and/or alkoxylated isoprenol and/or alkoxylated (meth) allyl alcohol and/or a vinylated methylpolyalkylene glycol, the monomers preferably each having an alkylene oxide group in the form of polymerized units having an arithmetic average of from 6 to 300.

10. Polymer composition according to one of claims 1 to 9, characterized in that the copolymers H and K each have polyether macromonomer building blocks and/or acid monomer building blocks of the same or different type.

11. Polymer composition according to one of claims 1 to 10, characterized in that at least 45 mol%, preferably at least 80 mol%, of all the structural units of the copolymers H and K are prepared by incorporating the acid monomer and the polyether macromonomer in the form of polymerized units.

12. A dispersant comprising at least 30% by weight of water and at least 10% by weight of the polymer composition according to any one of claims 1 to 11.

13. A dispersant as claimed in claim 12 in the form of an aqueous solution.

14. A process for preparing a polymer composition according to one of claims 1 to 11 or a dispersant according to claim 12 or 13, characterized in that the copolymers H and K are prepared separately in aqueous solution and the separately prepared copolymers or the separately prepared aqueous solutions are then mixed with one another.

15. A process according to claim 14, characterized in that the acid monomer and the polyether macromonomer are reacted in aqueous solution by radical polymerization using a peroxide-containing redox initiator system, the aqueous solution having a temperature of 10 to 45 ℃ and a pH of 3.5 to 6.5 during the polymerization.

16. Use of a polymer composition according to any one of claims 1 to 11 as a dispersant for hydraulic binders and/or latent hydraulic binders.