Inorganic binder composition comprising a copolymer

Abstract

The present invention relates to a composition comprising () at least one inorganic binder and () at least one water-soluble copolymer based on (a) 0.1 to 20 wt % of at least one monomer of the formula (I) and (b) 25 to 99.9 wt % of at least one hydrophilic monomer (b) which is different from monomer (a), where the at least one copolymer has a molar mass average M of 1 500 000 to 30 000 000 g/mol. Furthermore, a process for producing this composition is disclosed. A further aspect of the present invention is the use of the copolymer of component () as rheological additive in a composition of the invention.

Claims

1. A composition comprising () at least one inorganic binder () at least one water-soluble copolymer based on (a) 0.1 to 20 wt % of at least one monomer of the formula (I),
H.sub.2CC(R.sup.1)R.sup.2O(CH.sub.2CH.sub.2O).sub.k(CH.sub.2CH(R.sup.3)O).sub.l(CH.sub.2CH.sub.2O).sub.mR.sup.4 (I) where the units (CH.sub.2CH.sub.2O).sub.k, (CH.sub.2CH(R.sup.3)O).sub.l and (CH.sub.2CH.sub.2O).sub.m are arranged in a block structure in the order shown in formula (I) and the radicals have the following meanings: k: is from 10 to 150; l : is from 5 to 25; m: is from 1 to 15; R.sup.1: is H or methyl; the radicals R.sup.2: are each, independently of one another, a single bond or a divalent, linking group selected from the group consisting of (C.sub.nH.sub.2n) and O(C.sub.nH.sub.2n) and C(O)O(C.sub.nH.sub.2n), where n, n and n are each a natural number from 1 to 6; R.sup.3: is a hydrocarbon radical having at least 2 carbon atoms or an ether group of the general formula CH.sub.2OR.sup.3, where R.sup.3 is a hydrocarbon radical having at least 2 carbon atoms and the radicals R.sup.3 can be identical or different within the group (CH.sub.2CH(R.sup.3)O).sub.l; the radicals R.sup.4: are each, independently of one another, H or a hydrocarbon radical having 1 to 4 carbon atoms, and (b) 25 to 99.9 wt % by weight of at least one monoethylenically unsaturated, hydrophilic monomer (b) different from monomer (a), where the wt % figures are in each case based on the total amount of all monomers in the copolymer and the at least one copolymer has a molar mass average M of 1 500 000 to 30 000 000 g/mol which is determined by the Mark-Houwink relationship (1)
M=([]/K).sup.1/(1), where K=0.0049, =0.8 and [] is the intrinsic viscosity.

2. The composition according to claim 1, wherein the inorganic binder is at least one from the series calcium sulfate n-hydrate, Portland cement, white cement, calcium aluminum cement, calcium sulfoaluminum cement, geopolymer, and latent hydraulic and/or pozzolanic binder.

3. The composition according to claim 1, wherein the index k is from 23 to 26.

4. The composition according to claim 1, wherein the index l is from 8.5 to 17.25.

5. The composition according to claim 1, wherein the radicals have the following meanings: k: is from 23 to 26; l: is from 12.75 to 17.25; m: is from 2 to 5; R.sup.1: is H; R.sup.2: is a divalent, linking group O(C.sub.nH.sub.2n), where n is 4; R.sup.3: is a hydrocarbon radical having 2 carbon atoms; R.sup.4: is H.

6. The composition according to claim 1, wherein at least one of the monomers (b) is a monomer comprising acidic groups, the acidic groups comprising at least one group selected from the group of COOH, SO.sub.3H and PO.sub.3H.sub.2 and salts thereof.

7. The composition according to claim 1, which comprises at least two different monoethylenically unsaturated, hydrophilic monomers (b), namely at least one neutral hydrophilic monomer (b1), and at least one hydrophilic anionic monomer (b2) which comprises at least one acidic group selected from the group of COOH, SO.sub.3H and PO.sub.3H.sub.2 and salts thereof.

8. The composition according to claim 1, wherein the at least one copolymer is a copolymer based on at least one monomer (a) of the formula (I), and also acrylamide as neutral hydrophilic monomer (b1) and acrylamido-2-methylpropanesulfonic acid (AMPS) as anionic hydrophilic monomer (b2).

9. The composition according to claim 1, wherein the component () further comprises (c) at least one nonionic, nonpolymerizable, surface-active component.

10. The composition according to claim 1, which comprises, based on its dry mass, at least 20 wt % of the at least one inorganic binder and 0.0005 to 5 wt % of the at least one copolymer.

11. A process for producing a composition according to claim 1, wherein the monomer (a) of the general formula (I) is prepared by a process comprising the following steps: a) reaction of a monoethylenically unsaturated alcohol A1 of the general formula (II)
H.sub.2CC(R.sup.1)R.sup.2OH(II), with ethylene oxide, where the radicals R.sup.1 and R.sup.2 are as defined; with addition of an alkaline catalyst K1 comprising KOMe and/or NaOMe; giving an alkoxylated alcohol A2; b) reaction of the alkoxylated alcohol A2 with at least one alkylene oxide Z of the formula (Z) ##STR00002## where R.sup.3 is as defined; with addition of an alkaline catalyst K2; where the concentration of potassium ions in the reaction in step b) is less than or equal to 0.9 mol %, based on the alcohol A2 used; and the reaction in step b) is carried out at a temperature of less than or equal to 135 C., giving an alkoxylated alcohol A3 of the formula (III),
H.sub.2CC(R.sup.1)R.sup.2O(CH.sub.2CH.sub.2O).sub.k(CH.sub.2CH(R.sup.3)O).sub.lH(III) where the radicals R.sup.1, R.sup.2, R.sup.3, k and l are as defined; c) reaction of the alcohol A3 with ethylene oxide; giving an alkoxylated alcohol A4 which corresponds to the monomer (a) of the formula (I) where R.sup.4H and m=1 to 15; d) optionally etherification of the alkoxylated alcohol A4 with a compound
R.sup.4X where R.sup.4 is a hydrocarbon radical having 1 to 4 carbon atoms and X is a leaving group, optionally selected from the group consisting of Cl, Br, I, OSO.sub.2CH.sub.3 (mesylate), OSO.sub.2CF.sub.3 (triflate) and OSO.sub.2OR.sup.4; giving a monomer (a) of the formula (I) where R.sup.4=hydrocarbon radical having 1 to 4 carbon atoms.

12. A process for producing a composition as claimed in claim 1, wherein the copolymer is prepared by subjecting at least one monomer (a) and at least one hydrophilic monomer (b) to an aqueous solution polymerization.

13. The process according to claim 12, wherein the solution polymerization is carried out at a pH in the range from 5.0 to 9.

14. The process according to claim 12, wherein the solution polymerization is carried out in the presence of at least one surface-active component (c).

15. A process comprising utilizing the copolymer of component () as rheological additive in a composition according to claim 1.

Description

EXAMPLES

(1) Preparation of Monomer M1:

(2) A 1 l stirred stainless steel autoclave was charged with 44.1 g of hydroxylbutyl vinyl ether. Then 3.12 g of KOMe (32% strength in MeOH) were metered in and the methanol was stripped off at 80 C. and about 30 mbar. This was followed by heating to 140 C.; the reactor was flushed with nitrogen and an initial nitrogen pressure of 1.0 bar was set. Then 368 g of ethylene oxide (EO) were metered in over the course of about 3 h. After half an hour of subsequent reaction at 140 C., the reactor was cooled to 125 C. and a total of 392 g of pentene oxide (PeO) were metered in over the course of 3.5 h. The subsequent reaction ran over night.

(3) A hydroxylbutyl vinyl ether alkoxylate with 22 EO units and 12 PeO units (monomer M1) is obtained. The product had an OH number of 31.9 mg KOH/g (theoretical: 26.5 mg KOH/g). The OH number was determined by means of the acetic anhydride (AAn) method.

(4) Preparation of Monomer M2:

(5) A 2 l pressure autoclave with anchor stirrer was charged with 135.3 g (1.16 mol) of hydroxybutyl vinyl ether (HBVE) (stabilized with 100 ppm of potassium hydroxide (KOH)) and the stirrer was engaged. 1.06 g of potassium methoxide (KOMe) solution (32% KOMe in methanol (MeOH), corresponding to 0.0048 mol of potassium) were run in, and the stirred vessel was evacuated to a pressure of less than 10 mbar, heated to 80 C., and operated for 70 min at 80 C. under a pressure of less than 10 mbar. MeOH was removed by distillation.

(6) In an alternative procedure, the potassium methoxide (KOMe) solution (32% KOMe in methanol (MeOH)) was run in and the stirred vessel was evacuated to a pressure of 10-20 mbar, heated to 65 C., and operated for 70 min at 65 C. under a pressure of 10-20 mbar. MeOH was removed by distillation.

(7) The vessel was flushed three times with N.sub.2 (nitrogen). Thereafter it was tested for pressure-tightness, adjusted to 0.5 bar overpressure (1.5 bar absolute), and heated to 120 C. After letdown of the vessel to 1 bar absolute, 1126 g (25.6 mol) of ethylene oxide (EO) were metered until p.sub.max was 3.9 bar absolute and T.sub.max was 150 C. Following addition of 300 g of EO, the metering was discontinued (about 3 h after the start), and a 30-minute pause was followed by letdown to 1.3 bar absolute. Then the remainder of the EO was metered in. The EO metering lasted, including letdown, for a total of 10 h.

(8) Stirring then took place to constant pressure at about 145-150 C. (1 h), after which the batch was cooled to 100 C. and was freed from low boilers under a pressure of less than 10 mbar for 1 h.

(9) In this case, a hydroxybutyl vinyl ether akolylate with 22 EO units was obtained.

(10) A 2 l pressure autoclave with anchor stirrer was charged with 588.6 g (0.543 mol) of hydroxybutyl vinyl ether alkoxylate with 22 EO units, and the stirrer was switched on. Thereafter 2.39 g of 50% strength NaOH solution (0.030 mol NaOH, 1.19 g NaOH) were added, reduced pressure of <10 mbar was applied, and the temperature was raised to 100 C. and maintained for 80 min in order to remove the water by distillation.

(11) N.sub.2 flushing was carried out three times. Thereafter the vessel was tested for pressure-tightness, 0.5 bar overpressure (1.5 bar absolute) was set, heating took place to 127 C., and after that the pressure was set to 1.6 bar absolute. 59.7 g (1.358 mol) of EO were metered in at 127 C.; p.sub.max was 3.9 bar absolute. After a 30-minute wait for constant pressure to become established, the vessel was let down to 1.0 bar absolute.

(12) 625.5 g (8.688 mol) of BuO (butylene oxide) were metered in at 127 C.; p.sub.max was 3.1 bar absolute. An interim letdown became necessary owing to the increase in fill level. The BuO feed was halted, reaction was allowed to take place for 1 h until pressure was constant, followed by letdown to 1.0 bar absolute. Thereafter the metered addition of BuO was continued. P.sub.max was still 3.1 bar (first letdown after 610 g BuO, total BuO metering 8 h including wait for letdown). After the end of the BuO feed, reaction was allowed to continue for 8 h, followed by heating to 135 C. Thereafter 83.6 g (1.901 mol) of EO were metered in at 135 C.; p.sub.max was 3.1 bar absolute. The end of the EO feed was followed by further reaction for 4 h. The batch was cooled to 100 C., residual oxide was stripped off until the pressure was below 10 mbar for at least 10 min. This was followed by the addition of 0.5% of water at 120 C. and by subsequent stripping until the pressure was below 10 mbar for at least 10 min. The reduced pressure was canceled out with N.sub.2, and 100 ppm of butylated hydroxytoluene (BHT) were added. The product was discharged at 80 C. under N.sub.2.

(13) A hydroxybutyl vinyl ether alkoxylate with 24.5 EO units, 16 BuO units and 3.5 EO units (monomer M2) is obtained. Analysis (mass spectrum, GPC, .sup.1H NMR in CDCl.sub.3, .sup.1H NMR in MeOD) confirmed the structure.

General Preparation Example for Copolymers A and B

(14) In a 2 l three-neck flask with stirrer and thermometer, the following components were mixed with one another: 290 g distilled water, 242.5 g acrylamido-2-methylpropanesulfonic acid, Na salt (50 wt % strength solution in water; 24.7 mol %), 1.2 g silicone defoamer, 2.4 g pentasodium diethylenetriaminepentaacetate (complexing agent), 228.8 g acrylamide (50 wt % strength solution in water; 75.2 mol %), 4.6 g monomers M1 (comparative example, copolymer B) or monomer M2 (inventive, copolymer A)

(15) The solution was adjusted to a pH of 6 using 20% strength aqueous sodium hydroxide solution, then rendered inert by flushing with nitrogen for 10 minutes and cooled to about 5 C. The solution was transferred to a plastic container, and then in succession 200 ppm of 2,2-azobis (2-amidinopropane) dihydrochloride (as a 1 wt % strength solution), 10 ppm of tert-butyl hydroperoxide (as a 0.1 wt % strength solution), 5 ppm of FeSO.sub.4.7H.sub.2O (as a 1 wt % strength solution) and 6 ppm of sodium bisulfit (as 1 wt % strength solution) were added. The polymerization was initiated by exposure to UV light (two Philips tubes; Cleo Performance 40 W). After about 2 h, the hard gel was taken from the plastic container and cut using scissors into gel cubes measuring approximately 5 cm5 cm5 cm. Before the gel cubes were comminuted using a conventional mincer, they were coated with a commercial release agent. The release agent is a polydimethylsiloxane emulsion, and was diluted 1:20 with water. The resulting gel granules were spread uniformly on drying racks and dried to constant weight in a forced-air drying cabinet under reduced pressure at about 90 to 120 C.

Preparation of Copolymer C Based on Monomer M2 (Comparative Example)

(16) A 2 l polymerization reactor with stirrer, reflux condenser, thermometer and inert gas connection was initially charged with 663.77 g of demineralized water. While stirring, 151.60 g (0.331 mol) of 2-acrylamido-2-methylpropanesulfonic acid, Na salt (50% solution in water), 1.0 g of Xiameter AFE-0400 (silicone defoamer), 142.68 g (1.00 mol) of acrylamide (50% solution in water) and 3.0 g of Trilon C (5% aqueous solution of the pentasodium salt of diethylenetriaminepentaacetic acid) were added. Subsequently, the pH was adjusted to 6.0 with a 5% NaOH solution and/or 5% H.sub.2SO.sub.4 solution. Thereafter, 2.85 g (0.0011 mol) of monomer M2 and 1.0 g of sodium hypophosphite (10% solution in water) as chain transfer agent were added. After the addition of 22.01 g of demineralized water, the pH was adjusted again to 6.0 with a 5% NaOH solution and/or 5% H.sub.2SO.sub.4 solution. The solution was inertized by purging with nitrogen for 10 minutes and heated to 60 C. This was followed by successive addition of 1.6 g of tetraethylenepentamine (20% by weight solution in water) and 10.0 g of sodium peroxodisulfate (20% by weight solution in water), in order to initiate the polymerization. After the temperature had peaked, 5.0 g of 2,2-azobis(2-methylpropion-amidine) dihydrochloride (10% solution in water) were added and then the mixture was stirred at 65 C. for another 1 hour, in order to complete the polymerization.

(17) Performance Tests

(18) The self-leveling calcium sulfate screed was composed of 39.55 parts by weight of anhydrite and 60.0 parts by weight of standard sand (DIN EN 196-1). As initiator, 0.45 parts by weight of potassium sulfate was added. The amount of water used was 14.0 parts by weight, corresponding to a water-binder ratio of 0.35. To plasticize the self-leveling calcium sulfate screed, a polycarboxylate ether was added. The amount of the polycarboxylate ether, at 0.04 parts by weight was selected so that the self-leveling calcium sulfate screed, without the addition of a copolymer, 5 min after addition of water achieved a Hgermann cone slump flow of 2805 mm.

(19) The self-leveling calcium sulfate screeds were produced in accordance with DIN EN 196-1:2005 in a mortar mixer with a capacity of approximately 5 liters. For mixing up, water, plasticizer, copolymer (see table 1) and anhydrite were placed into the mixing vessel. Immediately thereafter the mixing operation was commenced, with the fluidizer at a low speed (140 revolutions per minute (rpm)). After 30 seconds, the standard sand was added at a uniform rate over the course of 30 seconds to the mixture. The mixer was then switched to a higher speed (285 rpm), and mixing was continued for 30 seconds more. After that the mixer was held on for 90 seconds. During the first 30 seconds, the self-leveling calcium sulfate screed, which stuck to the wall and to the lower part of the bowl, was removed with a rubber scraper and put into the middle of the bowl. After the wait, the self-leveling calcium sulfate screed was mixed for a further 60 seconds at the higher mixing speed. The total mixing time was 4 minutes.

(20) In order to assess the effect of the copolymer on the flow properties of the self-leveling calcium sulfate screed, the slump flow was determined immediately after the end of the mixing operation on all samples, using the Hgermann cone with no compaction energy being supplied, in accordance with the SVB guidelines of the Deutscher Ausschuss fr Stahlbeton (German Reinforced Concrete Committee) (see: Deutscher Ausschuss fr Stahlbetonbau (Ed.): DAfStbGuidelines for self-compacting concrete (SVB guidelines), Berlin, 2003). The Hgermann cone (d.sub.top=70 mm, d.sub.bottom=100 mm, h=60 mm) was placed centrally on a dry glass plate having a diameter of 400 mm and was filled with self-leveling calcium sulfate screed up to the level provided. Immediately after leveling had taken place or 5 min after the first contact between anhydrite and water, the Hgermann cone was taken off, held over the slumping self-leveling calcium sulfate screed for 30 seconds to allow for dripping, and then removed. As soon as the slump flow came to a standstill, the diameter was determined, using a caliper gauge, at two axes lying at right angles to one another, and the average was calculated. The slump flow is a value characteristic of the flow limit of a self-leveling calcium sulfate screed (see: Roussel, N et al.: Cement and Concrete Research, vol. 35, no. 5, (2005), pp. 817-822). As the slump flow decreases, the processing properties of the self-leveling calcium sulfate screed deteriorate.

(21) In order to characterize the effect of the copolymer on the robustness of the self-leveling calcium sulfate screed with respect to sedimentation and bleeding (settling of water on the surface), 200 ml of the self-leveling calcium sulfate screed, after having been mixed up, were introduced into a glass cylinder with a diameter of 35 mm (see: A. Perrot et al./Cement and Concrete Research 42 (2012) pp. 937-944). After rest times of 30, 60 and 120 min, the height of the water film (bleed water) on the surface of the self-leveling calcium sulfate screed was measured. The higher the film of water on the surface of the mortar, the lower the stabilizing effect of the copolymer used. The results are summarized in table 1.

(22) TABLE-US-00001 TABLE 1 Results of the performance tests Amount added [Weight % Slump based on flow Height of water film in [mm] after Molar mass Stabilizer anhydrite] [cm] 0 min 30 min 60 min 120 min average M Reference without 0.000 28.4 0.000 0.042 0.161 0.289 copolymer Copolymer A based 0.030 24.1 0.000 0.000 0.035 0.127 7.2 .Math. 10.sup.6 g/mol on monomer M2 0.050 23.7 0.000 0.000 0.000 0.000 (inventive) 0.100 21.8 0.000 0.000 0.000 0.000 Copolymer B based 0.030 20.6 0.000 0.020 0.078 0.323 on monomer M1 0.050 20.7 0.000 0.000 0.000 0.037 (comparative 0.100 19.4 0.000 0.000 0.000 0.000 example) Copolymer C based 0.030 27.5 0.000 0.056 0.128 0.428 0.34 .Math. 10.sup.6 g/mol on monomer M2 0.050 27.0 0.000 0.000 0.128 0.287 (comparative example)

(23) The comparative example copolymer B is based on the disclosure content in U.S. Pat. No. 8,362,180 (example in column 27, line 40 to column 28, line 14 with monomer M2).

(24) An added amount of just 0.05 wt % of the copolymer A of the invention is sufficient to stop sedimentation completely after 120 min, it being possible to achieve a good slump flow at the same time.

(25) The molar mass average M of the copolymer of the invention was, as explained above, determined via the Mark-Houwink relationship (1). The parameters K and a are unknown for the present polymer-solvent pair. Therefore, the parameters for pure polyacrylamide in water were used (according to J. Klein, K-D Conrad, Makromol. Chem. 1980, 18, 227), i.e. K=0.0049 and =0.8.

(26) For the determination of the intrinsic viscosity [], a 0.5% solution of the copolymer in water was prepared. This was diluted with a buffer (116.66 g NaCl+32.26 g Na.sub.2HPO.sub.4*12H.sub.2O+1.795 g Na.sub.2HPO.sub.4*H.sub.2O in 2 liters of demineralized water), in order to obtain a c=0.01% polymer solution. The solution was analyzed with an Ubbelohde viscometer (at 20 C.; Ubbelohde capillary type 1). The intrinsic viscosity was determined via the run time of the 0.01% polymer solution, using the solvent without polymer as reference.

(27) The run time (t(polymer)) of the polymer solution was determined in comparison with the pure solvent (t.sub.s) as reference (t=t(polymer)t.sub.s). The intrinsic viscosity [] can be calculated therefrom according to Solomon-Ciuta:
[]={square root over (2(v.sub.relative1)2lnv.sub.relative)})/c
with V.sub.relative=cv.sub.reduced+1
and V.sub.reduced=.sup.t/(ct.sub.s)