Additive for hydraulically setting compositions

Abstract

The present invention relates to an additive for hydraulically setting compositions, comprising a colloidally disperse preparation of at least one salt of a mono- or polyvalent metal cation and of at least one compound which is able to release an anion which forms a low-solubility salt with the metal cation, and of at least one polymeric sulphonated dispersant. The additive is suitable particularly as a slump retainer.

Claims

1. An additive for hydraulically setting compositions, comprising a colloidally disperse preparation of at least one salt of a mono- or polyvalent metal cation, at least one compound which is able to release an anion which forms a low-solubility salt with the metal cation, and a dispersant comprising 70 to 100% by weight of the total dispersant of a polymeric sulfonated dispersant having anionic and/or anionogenic groups which is selected from sulfonated ketone-formaldehyde condensates, sulfonated melaminesulfonate-formaldehyde condensates, naphthalenesulfonate-formaldehyde condensates, lignosulfonates and sulfonated copolymers obtained by radical copolymerization and where the metal cation is selected from Ca.sup.2+, Al.sup.3+, Fe.sup.3+, Fe.sup.2+, Zn.sup.2+, Mn.sup.2+, Cu.sup.2+, Mg.sup.2+, Sr.sup.2+, Ba.sup.2+, Li.sup.+, and mixtures thereof, and where the metal cation is present in a quantity such that the following condition (a) is met: $\begin{array}{cc}0.1<\frac{{.Math.}_i{z}_{K,i}*n_{K,i}}{{.Math.}_j{z}_{S,j}*n_{S,j}}<30& \left(a\right)\end{array}$ where z.sub.K,i is the amount of the charge number of the metal cation, n.sub.K,i is the number of mols of the weighed-in metal cation, z.sub.S,j is the amount of the charge number of the anionic and anionogenic groups present in the polymeric dispersant, n.sub.S,j is the number of mols of the anionic and anionogenic groups present in the weighed-in polymeric sulfonated dispersant, the indices i and j are independent of one another and are an integer greater than 0, where i is the number of different kinds of metal cations and j is the number of different kinds of anionic and anionogenic groups present in the polymeric dispersant.

2. The additive according to claim 1, where at least one metal cation and at least one anion are present in an amount calculated according to the following formulae: $\begin{array}{cc}0.01\le \frac{{.Math.}_l{z}_{A,l}.Math.n_{A,l}}{{.Math.}_i{z}_{K,i}.Math.n_{K,i}}<3& \left(b\right)\end{array}$ where z.sub.K,i is the amount of the charge number of the metal cation, n.sub.K,i is the number of mols of the weighed-in metal cation, z.sub.A,l is the charge number of the weighed-in anion, n.sub.A,l is the number of mols of the weighed-in anion, the indices i and 1 are independent of one another and are an integer greater than 0, i is the number of different kinds of metal cations and 1 is the number of different kinds of anions which are able to form a low-solubility salt with the metal cation.

3. The additive according to claim 1, where the anion is selected from an aluminate, a phosphate and a silicate.

4. The additive according to claim 1, where the cation is selected from Ca.sup.2+, Al.sup.3+, Fe.sup.3+,and Mg.sup.2+.

5. The additive according to claim 1, further comprising at least one neutralizing agent.

6. The additive according to claim 5, where the neutralizing agent is an organic monoamine, polyamine, ammonia or an alkali hydroxide.

7. The additive according to claim 1, having a pH of 2 to 13.

8. The additive according to claim 1, where the polymeric sulfonated dispersant is the sole dispersant or where the dispersant additionally comprises at least one polymeric dispersant comprising anionic and/or anionogenic groups and polyether side chains.

9. The additive according to claim 8, where the dispersant comprises 70 to 90% by weight of polymeric sulfonated dispersant and 10 to 30% by weight of the polymeric dispersant comprising anionic and/or anionogenic groups and polyether side chains.

10. The additive according to claim 1, obtained by precipitating the salt of the polyvalent metal cation in the presence of the polymeric sulfonated dispersant, to give a colloidally disperse preparation of the salt, or obtained by dispersing a freshly precipitated salt of the polyvalent metal cation in the presence of the polymeric sulfonated dispersant, to give a colloidally disperse preparation of the salt.

11. The additive according to claim 10, where a neutralizing agent is added to the colloidally disperse preparation.

12. The additive according to claim 1, obtained by peptizing a hydroxide and/or oxide of the polyvalent metal cation with an acid, to give a colloidally disperse preparation of the salt of the polyvalent metal cation.

13. A process for preparing the additive for hydraulically setting compositions according to claim 1, where the salt of the polyvalent metal cation is precipitated in the presence of the polymeric sulfonated dispersant, to give a colloidally disperse preparation of the salt, or where a freshly precipitated salt of the polyvalent metal cation is dispersed in the presence of the polymeric sulfonated dispersant, to give a colloidally disperse preparation of the salt.

14. A process comprising adding the additive for hydraulically setting compositions according to claim 1 as a slump retainer in water-containing building material mixtures which comprise a hydraulic binder.

15. The process according to claim 14, where the hydraulic binder is selected from cement, slag sand, fly ash, silica dust, metakaolin, natural pozzolans, burnt oil shale, calcium aluminate cement, calcium sulfate-based binders and/or mixtures of two or more thereof.

16. A building material mixture comprising the additive according to claim 1 and a binder selected from cement, slag sand, fly ash, silica dust, metakaolin, natural pozzolans, burnt oil shale, calcium aluminate cement, calcium sulfate-based binders and/or mixtures of two or more thereof.

17. The additive according to claim 1, wherein the dispersant comprises 80 to 100% by weight of the total dispersant of the polymeric sulfonated dispersant.

18. The additive according to claim 1, wherein the dispersant comprises 90 to 100% by weight of the total dispersant of the polymeric sulfonated dispersant.

19. The additive according to claim 8, where the dispersant comprises 80 to 90% by weight of polymeric sulfonated dispersant and 10 to 20% by weight of the polymeric dispersant comprising anionic and/or anionogenic groups and polyether side chains.

20. The additive according to claim 12, where the acid is selected from boric acid, carbonic acid, oxalic acid, silicic acid, polyphosphoric acid, sulfuric acid, phosphoric acid, phosphorous acid, an Al.sup.3+ hexaaquo complex and/or an Fe.sup.3+ hexaaquo complex.

Description

EXAMPLES

(1) General Synthesis Instructions

(2) Polymers used: the melamine-formaldehyde-sulfonate condensate Melment L10 and the β-naphthalenesulfonate-formaldehyde condensate Melcret 500L are commercial products from BASF Construction Solutions GmbH. Na lignosulfonate (M.sub.w 52 kDa, M.sub.n 7 kDa) was acquired from Sigma-Aldrich. The sulfonated acetone-formaldehyde condensate (AFS) was synthesized as follows:

(3) 35.0 g of sodium sulfite are introduced into 50 g of water in a three-necked flask with intensive reflux condenser, and stirred together thoroughly. Then 29 g of acetone are added. The solution is heated to 56° C. Then 117 g of 37% strength formaldehyde solution are slowly added dropwise, at a rate such that the temperature does not exceed 60° C. After the end of the addition, the solution is heated to 90° C. and stirred at that temperature for 1 hour. After cooling, it is neutralized with 50% strength sodium hydroxide solution. A red-brown solution with a strength of 40% is obtained. The molecular weight is 19 000 g/mol.

(4) The charge density is calculated from the initial masses, i.e.

(5) n(SO.sub.3.sup.−)=35 g/126.04 g/mol=0.278 mol; accordingly, 0.278 mol of charges on a total solids of 35.0 g+29 g+117*0.37=107.3 g gives a charge density of

(6) 0.278 mol/107.3 g=2.59 mmol/g.

(7) The charge density of Na lignosulfate was calculated on the basis of the idealized structural formula of the lignosulfonate monomer indicated below (after P. R. Gupta, J. L. McCarthy, Macromolecules 1968, 1, 495-498). Consequently, with z.sub.S,sulfonate=1, the resulting charge density is 3.76 mmol/g polymer.

(8) ##STR00018##

(9) TABLE-US-00001 TABLE 1 Physical data of the reference polymers V3 acetone V1 V2 condensate Melment L10 Na-lignosulfonate (AFS) Σ.sub.jz.sub.S, j × n.sub.s, j in mmol 4.29 3.76 2.59 per gram of polymer
General Instructions for Synthesizing the Additives

(10) The aqueous solutions of the polymers are mixed with the metal cation salts of the invention, with the anion compounds of the invention, and also, optionally, with a base or acid for adjusting the pH, with stirring. Mixing is carried out in a 1 l jacketed glass reactor with paddle stirrer, temperature-conditioned at 20° C., at 300 rpm. The sequence of the addition is indicated in Table 2 by a letter code. P stands for the aqueous solution of the polymer, K for the metal cation salt of the invention, A for the anion compound of the invention, and B and S for base and acid, respectively. The amounts are always based on the solid contents. The final pH of the resulting solutions or suspensions is likewise indicated.

(11) The metered additions of the respective components can be made quickly, in other words with a metering rate in the range of kg/s (for example, by rapid addition of a glass beaker with an aqueous solution of the respective component), or the respective components can be metered in slowly by means of controlled metering, by means of a perfusor pump, for example, in the g/h range.

(12) TABLE-US-00002 TABLE 2 Composition of the additives 1-10 No. Poly- mer Metal salt Anion com- pound Base/acid pH Seq- uence Water (% by weight) Polymer (% by weight) Metal salt (% by weight) Anion com- pound (% by weight) Base/acid (% by weight) $\frac{{.Math.}_i{z}_{K,i}*n_{K,i}}{{.Math.}_j{z}_{S,j}*n_{S,j}}$ $\frac{{.Math.}_l{z}_{A,l}\times n_{A,l}}{{.Math.}_j{z}_{K,i}\times n_{K,i}}$ 1 ligno- Ca(NO.sub.3).sub.2 NaAlO.sub.2 — 10.2 PKA 87.3 6.5 4.9 1.2 — 2.44 0.25 sul- fonate 2 Mel- Ca(NO.sub.3).sub.2 NaAlO.sub.2 HNO.sub.3 11.1 PKAS 75.8 9.3 9.8 4.9 0.2 3 0.5 ment L10 3 AFS Ca(NO.sub.3).sub.2 NaAlO.sub.2 HNO.sub.3 10.5 PKAS 69.7 15.3 9.7 4.9 0.4 3 0.5 4 AFS Ca(NO.sub.3).sub.2 NaAlO.sub.2 HNO.sub.3 12.0 PKAS 79.1 11.8 5.0 3.8 0.3 2 0.75 5 AFS Ca(NO.sub.3).sub.2 NaAlO.sub.2 HNO.sub.3 11.1 PKAS 74.1 11.8 10.0 3.8 0.3 4 0.38 8 AFS Ca(NO.sub.3).sub.2 NaAlO.sub.2 HNO.sub.3 10.5 PKAS 79.2 11.8 7.5 1.3 0.2 3 0.17 7 AFS Sr(NO.sub.3).sub.2 NaAlO.sub.2 HNO.sub.3 11.4 PKAS 77.5 7.6 7.9 2.4 4.6 3 0.5 8 AFS Zn(NO.sub.3).sub.2 NaAlO.sub.2 NaOH 10.2 PKAB 68.9 12.1 13.9 3.8 1.3 3 0.5 9 AFS Mg(NO.sub.3).sub.2 NaAlO.sub.2 NaOH 10.5 PKAB 77.4 12.0 7.9 1.3 1.4 2 0.25 10 AFS Al(NO.sub.3).sub.3 H.sub.3PO.sub.4 NH.sub.4OH 4 PKAB 69.4 11.7 17.1 0.7 1.1 4.5 0.17
Application Tests
Mortar Tests

(13) The mortar tests used were standard mortar tests in accordance with DIN EN 1015 using Bernburg cement CEM I 42.5 R and a w/c of 0.42. The weight ratio of sand to cement was 2.2 to 1. A mixture of 70% by weight standard sand (Normensand GmbH, D-59247 Beckum) and 30% by weight quartz sand was used. Prior to testing in the mortar, the polymer samples were defoamed using 1% by weight of triisobutyl phosphate, based on the polymer solids content.

(14) The spread is obtained by shaking the slump flow table, in accordance with the aforementioned DIN method, by raising and impacting 15 times. The shearing forces which occur as a result of the tapping caused further spreading of the mortar. The diameter of the mortar cake after tapping is identified as the spread.

(15) The addition figures reported are based always on the solids content of the polymer suspensions used, not on the active polymer content.

(16) TABLE-US-00003 TABLE 3 Mortar results, Bernburg cement, w/c 0.42 Additive Addition Spread [cm] Delta 30-4 Delta 60-4 No. Base polymer [%] 4 min 10 min 30 min 60 min 90 min [cm] [cm] V1 Melment L10 0.5 28.9 27.1 24.3 21.7 −4.6 −7.2 V2 Na lignosulfonate 0.6 25.3 24.2 19.8 −5.5 V3 AFS 0.5 26.8 25.4 22.4 20.6 19.7 −4.4 −6.2 1 Na lignosulfonate 2.5 16.5 18.2 19.8 19.7 +3.2 2 Melment L10 2.2 17.4 26.4 27.5 25.3 22.7 +10.1 +7.9 3 AFS 1.5 17.1 26 27.8 25.1 22.5 +10.7 +8.0 4 AFS 1.7 17.9 26.8 27.3 24.2 22.7 +9.4 5 AFS 1.7 17 26.8 27.9 25 22.2 +10.9 +8.0 6 AFS 1.2 23.7 29.2 28.3 25.5 23.3 +4.6 +1.8 7 AFS 1.5 17.7 24.6 25 23.3 21.6 +7.3 +5.6 8 AFS 1.7 18.5 22.9 20 +1.5 9 AFS 2.0 14.2 14.4 14.8 +0.6 10 AFS 1.5 16.7 17.2 17.8 17.2 17 +1.1 +0.5
Concrete Tests

(17) Concrete tests conducted were standard concrete tests in accordance with DIN EN 12350 with a cement content of 380 kg. The grading curve set corresponds to the A/B 16 classification according to DIN 1045-2. The cement used was Bernburg CEM I 42.5 R, with a w/c of 0.44. Prior to testing in the concrete, the polymer samples were defoamed with 1% by weight of triisobutyl phosphate, based on the polymer solids content.

(18) Mixing Process

(19) The dried aggregates as per grading curve, and the cement, are introduced into a forced mixer and mixed for 10 seconds. The mixture in the forced mixer is thereafter moistened with 10% of the total water, and mixing is continued for a further 2 minutes. Thereafter the remainder of the water is added, and mixing is continued for 1 minute more. Lastly the additive of the invention is added, followed by mixing for 1 minute again.

(20) The slump value is a measure of the extent to which the concrete cake collapses after the metal cone is lifted (difference in height between the top edge of the metal cone and the height of the concrete cake after removal of the metal mould). The slump flow corresponds to the base diameter of the concrete cake after collapse.

(21) The spread is obtained by shaking the slump flow board, in accordance with the abovementioned DIN method, by raising and impacting 15 times. The shearing forces which occur as a result of the tapping produce a further spread of the concrete. The diameter of the concrete cake after tapping is identified as the spread.

(22) The additions reported are based in each case on the solids content of the polymer suspensions used, not on the active polymer content.

(23) The results are summarized in Table 4 below.

(24) TABLE-US-00004 TABLE 4 Results of the concrete tests, cement: Bernburg CEM I 42.5 R, w/c = 0.44 Slump in cm Slump flow in cm No. Plasticizer Addition % Air % 0 min 10 min 30 min 60 min 0 min 10 min 30 min 60 min Na 0.65 1.40 19.0 14.5 6.5 4.0 30.0 27.0 21.0 20.0 lignosulfonate Melment L10 0.5 1.70 21.0 16.0 5.0 2.0 36.5 28.0 20.5 20.0 AFS 0.55 1.60 24.0 21.5 5.0 2.0 46.0 35.0 20.5 20.0 1 Na 2.40 1.65 1.0 1.5 5.0 5.0 20.0 20.0 20.5 20.5 lignosulfonate 2 Melment 3.40 1.25 0.0 15.0 23.0 15.0 20.0 27.0 43.0 27.5 3 AFS 1.60 1.55 1.0 4.0 22.5 16.0 20.0 20.0 38.5 28.0 Compressive Spread in cm Delta spread strength 24 h No. Plasticizer 0 min 10 min 30 min 60 min 10-0 min 30-0 min N/mm.sup.2 Na 51.0 47.0 43.0 37.0 −4.0 −8.0 3.65 lignosulfonate Melment L10 56.0 49.0 42.5 38.0 −7.0 −13.5 26.45 AFS 58.5 52.5 41.5 38.0 −6.0 −17.0 25.65 1 Na 36.0 38.5 41.0 40.0 +2.5 +5.0 — lignosulfonate 2 Melment 36 50.0 56.0 45.0 +14.0 +20.0 24.0 3 AFS 36.0 42.0 55.0 45.0 +6.0 +19.0 24.6

(25) As the mortar and concrete results show, the additives of the invention produce retention of consistency for longer, across the board, than additives comprising the unmodified sulfonated polymeric dispersants.

(26) The concrete strengths after 24 h for the inventively modified comb polymers are very close to the strength of the unmodified reference. This proves the outstanding suitability of the inventive preparations as slump retainers with excellent early-strength development.

(27) Additives 11 to 18 were synthesized according to the general instructions given above. Their composition is summarized in Table 5 below.

(28) Application Tests

(29) The additives were used in mortar tests which were standard mortar tests in accordance with DIN EN 1015 using Mergelstetten cement CEM I 42.5 R and a w/c of 0.425. The weight ratio of sand to cement was 2.2 to 1. A mixture of 70% by weight standard sand (Normensand GmbH, D-59247 Beckum) and 30% by weight quartz sand was used. Prior to testing in the mortar, the polymer samples were defoamed using 1% by weight of triisobutyl phosphate, based on the polymer solids content. The tests were carried out as described above and the results are given in Table 6 below.

(30) TABLE-US-00005 TABLE 5 Composition of the additives nos. 11-18 Metall- Anion- Reihen- Wasser No. Polymer Salze Verb. Base/Säure pH folge (M %) 11 Clayton Mg(NO.sub.3).sub.2 NaAlO.sub.2 NaOH 10.7 PKAB 77.7 12 Clayton Mg(NO.sub.3).sub.2 NaAlO.sub.2 NaOH 10.7 PKAB 78.2 13 Clayton Ca(NO.sub.3).sub.2 NaAlO.sub.2 HNO.sub.3 PKAB 83.3 14 Clayton Ca(NO.sub.3).sub.2 NaAlO.sub.2 HNO.sub.3 10.9 PAKS 83.0 15 Clayton Ca(NO.sub.3).sub.2 NaAlO.sub.2 HNO.sub.3 10.9 PAKS 82.8 16 Clayton Ca(NO.sub.3).sub.2 NaAlO.sub.2 — 10.8 PAK 77.8 17 Clayton Ca(NO.sub.3).sub.2 NaAlO.sub.2 — 11.0 PAK 80.8 18 Clayton Ca(NO.sub.3).sub.2 NaAlO.sub.2 HNO.sub.3 11.0 PAKS 80.5     No.   Polymer (M %) Metall- Salz (M %) Anion- Verb. (M %)   Base/Säure (M %) $\frac{{.Math.}_i{z}_{K,i}*n_{K,i}}{{.Math.}_j{z}_{S,j}*n_{S,j}}$ $\frac{{.Math.}_l{z}_{A,l}*n_{A,l}}{{.Math.}_{-j}{z}_{K,-j}*n_{K,j-}}$ 11 11.9 7.9 1.0 1.5 2.0 0.2 12 11.8 7.8 0.5 1.7 2.0 0.1 13 11.0 4.7 0.9 0.1 2.0 0.2 14 11.0 4.7 1.2 0.2 2.0 0.25 15 11.0 4.7 1.4 0.2 2.0 0.30 16 12.9 8.2 1.1 0 3.0 0.13 17 11.0 7.0 1.2 0 3.0 0.17 18 11.0 7.0 1.4 0.1 3.0 0.2

(31) TABLE-US-00006 TABLE 6 Mortar results, cement Mergelstetten CEM I 42.5 R, w/c = 0.425 Spread [cm] Additive No. Dosage [%] 4 min 10 min 30 min 60 min 90 min Delta 30-4 [cm] Delta 60-4 [cm] 11 1.03 16.5 16.9 16.6 +0.1 — 12 1.03 15.2 15.4 15.1 −0.1 — 13 1.2 20.5 28.8 27.7 26.3 24.8 +7.2 +4.3 14 1.2 22.6 28.1 27.9 25.6 23.2 +5.3 +0.8 15 1.2 18.2 27.6 27 24.1 22.8 +8.8 +4.6 16 1.2 29.8 27.2 26.1 23.1 21.4 −3.7 −8.4 17 1.2 21.3 26.6 25.5 22.7 20.6 +4.2 −0.7 18 1.2 19.3 25.8 26 22.2 19.9 +6.7 +0.6 19 1.3 22.8 27.4 27.1 26.2 25.1 +4.3 +2.3 20 1.8 23.9 28.8 27.8 27.7 27.6 +3.9 +3.7 21 1.4 21.2 27.2 27.8 27.8 27.7 +6.6 +6.5