CALCIUM SULFATE COMPOSITION COMPRISING AN ADDITIVE

Abstract

The invention relates to a composition comprising at least 10 wt. % of a binder based on calcium sulfate and 0.005 to 5 wt. % of an additive made of at least one water-soluble salt of a multivalent metal cation, at least one compound which is capable of releasing an anion that forms a poorly soluble salt together with the multivalent metal cation, and at least one polymer dispersant which comprises anionic and/or anionogenic groups and polyether side chains. The invention further relates to a method for producing said composition and to the use thereof as a calcium sulfate flow screed, a flowable calcium sulfate filler compound, or an earth-moist calcium sulfate screed.

Claims

1. A composition comprising, based on the total mass of the composition: A) at least 10 wt % of a binder based on calcium sulfate and B) 0.005 to 5 wt % of an additive prepared from components comprising: i) at least one water-soluble salt of a polyvalent metal cation, ii) at least one compound able to release an anion which forms a sparingly soluble salt with the polyvalent metal cation, and iii) at least one polymeric dispersant which comprises an anionic and/or anionogenic group, and a polyether side chain, wherein the polyvalent metal cation being is at least one selected from the group consisting of Al.sup.3+, Fe.sup.3+, Fe.sup.2+, Cu.sup.2+, Mg.sup.2+, Ca.sup.2+, Sr.sup.2+, Ba.sup.2+ and mixtures thereof, the metal cation is present in an amount such that the relation according to formula (a) is greater than 0.1 and less than or equal to 30: $\begin{array}{cc}0.1<\frac{{}_i.Math.z_{K,i}{n}_{K,i}}{{}_j.Math.z_{s,j}{n}_{s,j}}30.& \left(a\right)\end{array}$ z.sub.K,i is the amount of the charge number of the polyvalent metal cation, n.sub.K,i is the number of moles of the polyvalent metal cation, z.sub.S,j is the amount of the charge number of the anionic and/or anionogenic group present in the polymeric dispersant, n.sub.S,j is the number of moles of the anionic and/or anionogenic group present in the polymeric dispersant, the indices i and j are independent of one another and are each an integer greater than 0, i is the number of different polyvalent metal cations, and j is the number of different anionic and/or anionogenic groups present in the polymeric dispersant.

2. The composition according to claim 1, wherein the polyvalent metal cation and the anion being are present in amounts satisfying the formulae: $\begin{array}{cc}0.1<\frac{{}_i.Math.z_{K,i}{n}_{K,i}}{{}_j.Math.z_{s,j}{n}_{s,j}}30& \left(a\right)\\ 0.01<\frac{{}_l.Math.z_{A,l}{n}_{A,l}}{{}_j.Math.z_{K,i}{n}_{K,i}}3,& \left(b\right)\end{array}$ z.sub.K,i is the amount of the charge number of the polyvalent metal cation, n.sub.K,i is the number of moles of the polyvalent metal cation, z.sub.S,j is the charge number of the anionic and/or anionogenic group present in the polymeric dispersant, n.sub.S,j is the number of moles of the anionic and/or anionogenic group present in the polymeric dispersant, z.sub.A,l is the charge number of the anion, n.sub.A,l is the number of moles of the anion, the indices i, j and l are independent of one another and are each an integer greater than 0, i is the number of different polyvalent metal cations, j is the number of different anionic and/or anionogenic groups present in the polymeric dispersant, and l is the number of different anions which are able to form a sparingly soluble salt with the metal cation.

3. The composition according to claim 1, wherein the anion is at least one selected from the group consisting of carbonate, oxalate, silicate, phosphate, polyphosphate, phosphite, borate, aluminate, ferrate, zincate and sulfate.

4. The composition according to claim 2, wherein the polyvalent metal cation and the anion are present in the additive in amounts satisfying the formula: $\begin{array}{cc}0.25<\frac{{\left({}_i.Math.z_{K,i}{n}_{K,i}\right)}^2}{\left({}_l.Math.z_{A,l}{n}_{A,l}\right).Math.\left({}_j.Math.z_{s,j}{n}_{s,j}\right)}<25.& \left(c\right)\end{array}$

5. The composition according to claim 1, wherein the additive further comprises at least one pH neutralizer.

6. The composition according to claim 5, wherein the pH neutralizer is at least one selected from the group consisting of alkali metal hydroxide, organic monoamine, organic diamine, organic polyamine and ammonia.

7. The composition according to claim 1, the polymeric dispersant comprising as the anionic and/or anionogenic group at least one structural unit of the general formula (Ia), (Ib), (Ic) and/or (Id): ##STR00025## R.sup.1 is H or an unbranched or branched C.sub.1-C.sub.4 alkyl group, CH.sub.2COOH or CH.sub.2COXR.sup.2; for X and R.sup.2, either X is NR.sup.3(C.sub.nH.sub.2n) or O(C.sub.nH.sub.2n) with n=1, 2, 3 or 4, the nitrogen atom or the oxygen atom, respectively, being attached to the CO group, and R.sup.2 is PO.sub.3M.sub.2, OPO.sub.3M.sub.2, (C.sub.6H.sub.4)PO.sub.3M.sub.2 or (C.sub.6H.sub.4)OPO.sub.3M.sub.2, Or X is a chemical bond and R.sup.2 is OM; R.sup.3 is H, C.sub.1-C.sub.6 alkyl, (C.sub.nH.sub.2n)OH, (C.sub.nH.sub.2n)PO.sub.3M.sub.2, (C.sub.nH.sub.2n)OPO.sub.3M.sub.2, (C.sub.6H.sub.4)PO.sub.3M.sub.2, (C.sub.6H.sub.4)OPO.sub.3M.sub.2 or (C.sub.nH.sub.2n)O-(AO)-R.sup.4; is an integer from 1 to 350; R.sup.4 is H or an unbranched or branched C.sub.1-C.sub.4 alkyl group; and M independently at each occurrence is H or one cation equivalent; ##STR00026## R.sup.5 is H or an unbranched or branched C.sub.1-C.sub.4 alkyl group; n is 0, 1, 2, 3 or 4; R.sup.6 is PO.sub.3M.sub.2 or OPO.sub.3M.sub.2; and M independently at each occurrence is H or one cation equivalent; ##STR00027## R.sup.7 is H or an unbranched or branched C.sub.1-C.sub.4 alkyl group; Z is O or NR.sup.8; and R.sup.8 is H.sub.s (C.sub.nH.sub.2n)OH, (C.sub.nH.sub.2n)PO.sub.3M.sub.2, (C.sub.nH.sub.2n)OPO.sub.3M.sub.2, (C.sub.6H.sub.4)PO.sub.3M.sub.2, or (C.sub.6H.sub.4)OPO.sub.3M.sub.2; n is 1, 2, 3 or 4, and M independently at each occurrence is H or one cation equivalent; ##STR00028## R.sup.9 is H or an unbranched or branched C.sub.1-C.sub.4 alkyl group; Q is NR.sup.10 or O; R.sup.10 is H, (C.sub.nH.sub.2n)OH, (C.sub.nH.sub.2n)PO.sub.3M.sub.2, (C.sub.nH.sub.2n)OPO.sub.3M.sub.2, (C.sub.6H.sub.4)PO.sub.3M.sub.2, (C.sub.6H.sub.4)OPO.sub.3M.sub.2 or (C.sub.nH.sub.2n)O-(AO).sub.R.sup.11; A is C.sub.xH.sub.2x with x=2, 3, 4 or 5 or is CH.sub.2CH(C.sub.6H.sub.5); is an integer from 1 to 350; R.sup.11 is H or an unbranched or branched C.sub.1-C.sub.4 alkyl group; n is 1, 2, 3 or 4; and M independently at each occurrence is H or one cation equivalent.

8. The composition according to claim 1, the polymeric dispersant comprising as polyether side chain at least one structural unit of the general formulae (IIa), (IIb), (IIc) and/or (IId): ##STR00029## R.sup.12, R.sup.13 and R.sup.14 independently of one another are each H or an unbranched or branched C.sub.1-C.sub.4 alkyl group; for E and G, either E is an unbranched or branched C.sub.1-C.sub.6 alkylene group, a cyclohexylene group, CH.sub.2C.sub.6H.sub.10, 1,2-phenylene, 1,3-phenylene or 1,4-phenylene, and G is O, NH or CONH, or E and G together are a chemical bond; A is C.sub.xH.sub.2x with x=2, 3, 4 or 5 or is CH.sub.2CH(C.sub.6H.sub.5); n is 0, 1, 2, 3, 4 and/or 5; a is an integer from 2 to 350; R.sup.15 is H, an unbranched or branched C.sub.1-C.sub.4 alkyl group, CONH.sub.2 and/or COCH.sub.3; ##STR00030## R.sup.16, R.sup.17 and R.sup.18 independently of one another are each H or an unbranched or branched C.sub.1-C.sub.4 alkyl group; E is an unbranched or branched C.sub.1-C.sub.6 alkylene group, a cyclohexylene group, CH.sub.2C.sub.6H.sub.10, 1,2-phenylene, 1,3-phenylene or 1,4-phenylene or is a chemical bond; A is C.sub.xH.sub.2x with x=2, 3, 4 or 5 or is CH.sub.2CH(C.sub.6H.sub.5); L is C.sub.xH.sub.2x with x=2, 3, 4 or 5 or is CH.sub.2CH(C.sub.6H.sub.5); a is an integer from 2 to 350; d is an integer from 1 to 350; R.sup.19 is H or an unbranched or branched C.sub.1-C.sub.4 alkyl group; R.sup.20 is H or an unbranched C.sub.1-C.sub.4 alkyl group; and n is 0, 1, 2, 3, 4 or 5; ##STR00031## R.sup.21, R.sup.22 and R.sup.23 independently of one another are each H or an unbranched or branched C.sub.1-C.sub.4 alkyl group; W is O, NR.sup.25 or N Y is 1 if W is O or NR.sup.25, Y is 2 if W is N; A is C.sub.xH.sub.2x with x=2, 3, 4 or 5 or is CH.sub.2CH(C.sub.6H.sub.5); a is an integer from 2 to 350; R.sup.24 is H or an unbranched or branched C.sub.1-C.sub.4 alkyl group; and R.sup.25 is H or an unbranched or branched C.sub.1-C.sub.4 alkyl group; ##STR00032## R.sup.26 is H or an unbranched or branched C.sub.1-C.sub.4 alkyl group; Q is NR.sup.10, N or O; Y is 1 if Q is O or NR.sup.28, Y is 2 if Q is N; R.sup.27 is H or an unbranched or branched C.sub.1-C.sub.4 alkyl group; R.sup.28 is H or an unbranched or branched C.sub.1-C.sub.4 alkyl group; A is C.sub.xH.sub.2x with x=2, 3, 4 or 5, or CH.sub.2C(C.sub.6H.sub.5)H; a is an integer from 2 to 350; and M independently at each occurrence is H or one cation equivalent.

9. The composition according to claim 1, wherein the polymeric dispersant is a polycondensation product comprising structural units (III) and (IV): ##STR00033## T is a substituted or unsubstituted phenyl or naphthyl radical or a substituted or unsubstituted hetero aromatic radical having 5 to 10 ring atoms, of which 1 or 2 atoms are heteroatoms selected from the group consisting of N, O and S; n is 1 or 2; B is N, NH or O, with the proviso that n is 2 if B is N and with the proviso that n is 1 if B is NH or O; A is C.sub.xH.sub.2x with x=2, 3, 4 or 5 or is CH.sub.2CH(C.sub.6H.sub.5); a is an integer from 1 to 300; and R.sup.29 is H, a branched or unbranched C.sub.1 to C.sub.10 alkyl radical, C.sub.5 to C.sub.8 cycloalkyl radical, aryl radical, or heteroaryl radical having 5 to 10 ring atoms, of which 1 or 2 atoms are heteroatoms selected from the group consisting of N, O and S; the structural unit (IV) is at least one selected from the group consisting of structural units (IVa) and (IVb): ##STR00034## D is a substituted or unsubstituted phenyl or naphthyl radical or a substituted or unsubstituted heteroaromatic radical having 5 to 10 ring atoms, of which 1 or 2 atoms are heteroatoms selected from the group consisting of N, O and S; E is N, NH or O, with the proviso that n is 2 if E is N and with the proviso that n is 1 if E is NH or O; A is C.sub.xH.sub.2x with x=2, 3, 4 or 5 or is CH.sub.2CH(C.sub.6H.sub.5); b is an integer from 1 to 300; and M independently at each occurrence is H or one cation equivalent; ##STR00035## V is a substituted or unsubstituted phenyl or naphthyl radical and is optionally substituted by 1 or two radicals selected from R.sup.31, OH, OR.sup.31, (CO)R.sup.31, COOM, COOR.sup.31, SO.sub.3R.sup.31 and NO.sub.2; R.sup.30 is COOM, OCH.sub.2COOM, SO.sub.3M or OPO.sub.3M.sub.2; R.sup.31 is C.sub.1-C.sub.4 alkyl, phenyl, naphthyl, phenyl-C.sub.1-C.sub.4 alkyl or C.sub.1-C.sub.4 alkylphenyl; and M independently at each occurrence is H or one cation equivalent.

10. The composition according to claim 1, characterized in that wherein the binder based on calcium sulfate is -hemihydrate, /-hemihydrate, -hemihydrate, natural anhydrite, synthetic anhydrite, anhydrite obtained from flue gas desulfurization, and/or mixtures of two or more thereof.

11. The composition according to claim 1, comprising at least one further binder selected from the group consisting of Portland cement, white cement, calcium aluminate cement, calcium sulfoaluminate cement, and pozzolanic binders such as flyash, metakaolin, silica dust and slag sand.

12. The composition according to claim 1, comprising at least one compound selected from the group consisting of silica sand, finely ground quartz, limestone, heavy spar, calcite, aragonite, vaterite, dolomite, talc, kaolin, mica, chalk, titanium dioxide, rutile, anatase, aluminum hydroxide, aluminum oxide, magnesium hydroxide and brucite.

13. A process for preparing the composition according to claim 1, the process comprising: contacting: a) the at least one water-soluble salt of a polyvalent metal cation, b) the at least one compound able to release an anion which forms a sparingly soluble salt with the polyvalent metal cation, and c) the at least one polymeric dispersant which comprises an anionic and/or anionogenic group and a polyether side chain, with one another in the presence of water, thereby obtaining an additive, and contacting the resulting additive with further components of the composition, comprising the binder based on calcium sulfate.

14. The composition according to claim 1, wherein the composition is self-leveling calcium sulfate screed, flowable calcium sulfate filling compound, or calcium sulfate screed of damp-soil consistency.

Description

EXAMPLES

Gel Permeation Chromatography

[0326] The sample preparation for the determination of molar weights took place by dissolving the polymer solution in the GPC buffer, to give a polymer concentration in the GPC buffer of 0.5% by weight. Thereafter this solution was filtered through a syringe filter with polyethersulfone membrane and a pore size of 0.45 m. The injection volume of this filtrate was 50-100 l.

[0327] The average molecular weights were determined on a GPC instrument from Waters with the model name Alliance 2690, with a UV detector (Waters 2487) and an RI detector (Waters 2410). [0328] Columns: Shodex SB-G Guard Column for SB-800 HQ series [0329] Shodex OHpak SB 804HQ and 802.5HQ [0330] (PHM gel, 8300 mm, pH 4.0 to 7.5) [0331] Eluent: 0.05 M aqueous ammonium formate/methanol mixture=80:20 (parts by volume) [0332] Flow rate: 0.5 ml/min [0333] Temperature: 50 C. [0334] Injection: 50 to 100 l [0335] Detection: RI and UV

[0336] The molecular weights of the polymers were determined with two different calibrations. Determination took place first of all relative to polyethylene glycol standards from the company PSS Polymer Standards Service GmbH. The molecular weight distribution curves of the polyethylene glycol standards were determined by means of light scattering. The masses of the polyethylene glycol standards were 682 000, 164 000, 114 000, 57 100, 40 000, 26 100, 22 100, 12 300, 6240, 3120, 2010, 970, 430, 194, 106 g/mol.

General Spray Drying Protocol

[0337] The additives of the invention can be converted into powder form by spray drying. In that case the aqueous solutions or suspensions of the additives of the invention are dried using a spray dryer (e.g. Mobil Minor from GEA Niro) at an entry temperature of about 230 C. and an exit temperature of about 80 C. For this purpose the aqueous solutions of the additives of the invention were initially admixed with 1% by weight (based on the solids content of the aqueous solution) of a mixture of Additin RC 7135 LD (antioxidant; Rhein Chemie GmbH) and a water-miscible solvent based on polyethylene glycol (Pluriol A 500 E, BASF SE), which is used in the same amount by weight as the aqueous solutions or suspension of the additives of the invention. The resulting powders are admixed with 1% by weight of finely divided silica (N20P, Wacker Chemie AG), ground using a Retsch Grindomix RM 200 mill at 8000 rpm for 10 seconds, and filtered through a 500 m sieve.

Polymer Synthesis

[0338] The comb polymer P1 is based on the monomers maleic acid, acrylic acid and vinyloxybutylpolyethylene glycol. The synthesis of the comb polymer P1 is described in WO 2010/066470 at page 10 line 1 to line 38.

[0339] The comb polymer P2 is based on the monomers acrylic acid and vinyloxybutylpolyethylene glycol. The synthesis of the comb polymer P2 is described in WO 2006/133933 at page 13 line 15 to line 26, the synthesis described having been modified by using 21.7 g of acrylic acid rather than the 26 g of acrylic acid described, and by using 8.3 g of NaOH (20%) rather than the 10 g of NaOH (20%) described.

Example Calculation of the Charge Density:

[0340] [00006]${}_j.Math.z_{S,j}{n}_{s,j}.Math..Math.\mathrm{in}.Math..Math.\mathrm{mmol}.Math..Math.\mathrm{per}.Math..Math.\mathrm{gram}.Math..Math.\mathrm{of}.Math..Math.\mathrm{polymer}=\frac{\begin{array}{c}n\left(\mathrm{number}.Math..Math.\mathrm{of}.Math..Math.\mathrm{moles}.Math..Math.\mathrm{of}.Math..Math.\mathrm{initial}.Math..Math.\mathrm{mass}.Math..Math.\mathrm{of}.Math..Math.\mathrm{acid}.Math..Math.\mathrm{monomers}.Math..Math.\mathrm{in}.Math..Math.\mathrm{mmol}\right).Math.\\ \mathrm{charge}.Math..Math.\mathrm{number}.Math..Math.\mathrm{of}.Math..Math.\mathrm{acid}.Math..Math.\mathrm{monomer}\end{array}}{\begin{array}{c}m\left(\mathrm{mass}.Math..Math.\mathrm{of}.Math..Math.\mathrm{polymer}.Math..Math.\mathrm{solution}.Math..Math.\mathrm{in}.Math..Math.g\right).\\ \mathrm{solids}.Math..Math.\mathrm{content}.Math..Math.\mathrm{of}.Math..Math.\mathrm{the}.Math..Math.\mathrm{polymer}.Math..Math.\mathrm{solution}.Math..Math.\mathrm{in}.Math..Math.\%\end{array}}$

Example Calculation for Polymer P2

[0341] [00007]${}_j.Math.z_{S,j}{n}_{s,j}=\frac{\left(18.6.Math..Math.\mathrm{mmol}.Math.1\right)}{\left(50.Math..Math.g.Math.43.1.Math.\%.Math.\text{/}.Math.100\right)}=0.86.Math..Math.\mathrm{mmol}.Math.\text{/}.Math.g$

TABLE-US-00001 TABLE 1 Physical data of the comb polymers P1 P2 .sub.j z.sub.S,j n.sub.s,j in mmol per gram of polymer 0.93 0.86 Mw (GPC) 40 000 50 000

Examples of Preparation of the Additives of the Invention

General Protocol:

[0342] The aqueous solution of the comb polymer is mixed with the metal cation salts of the invention, with the anion compounds of the invention, and also, optionally, with a base or acid to adapt 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 the table by a letter code. P stands for the aqueous solution of the comb 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. A code of PKAB, for example, means that the polymer P is introduced initially, then the metal cation salt K is added. Thereafter the anion compound A and the base B are added. The amounts are always based on the solids contents. The final pH of the resulting solutions or suspensions is likewise indicated.

Example Calculation of Formula (a) on the Basis of Example 1:

[0343] The corresponding masses are taken from the table of initial masses: Mass of polymer P1 14.71 g and mass of Ca(OH).sub.2 1.46 g.

therefore
n.sub.K=1.46 g/74.1 g/mol=19.7 mmol,
n.sub.S=14.71 g.Math.0.86 mmol/g=12.65 mmol and

[00008]$\frac{{}_i.Math.z_{K,i}{n}_{K,i}}{{}_j.Math.z_{S,j}{n}_{s,j}}=\frac{19.7.Math..Math.\mathrm{mmol}.Math.2}{12.65.Math..Math.\mathrm{mmol}.Math.1}=3.12$

Examples of Additives of the Invention are Compiled in Tables 2 to 5 Below:

[0344]

TABLE-US-00002 TABLE 2 Composition of the liquid precursors of the examples of the invention No. Poly- mer Metal salts Anion comp. Base/ acid pH Sequence Water (m %) Polymer (m %) Metal salt 1 (m %) Acid (m %) Anion comp. (m %) Base (m %) [00009]$\frac{\underset{i}{.Math.}.Math.z_{K,i}*n_{K,i}}{\underset{j}{.Math.}.Math.z_{S,j}*n_{S,j}}$ [00010]$\frac{\underset{l}{.Math.}.Math.z_{A,l}{n}_{A,l}}{\underset{j}{.Math.}.Math.z_{K,i}{n}_{K,i}}$ 1 P2 Ca(OH).sub.2 H.sub.3P NaO 10, PKSAB 78.24 14.71 1.46 3.68.sup.1 0.64 1.27 3.12 0.5 2 P1 Ca(OH).sub.2 H.sub.3P NaO 9.4 PKSAB 76.7 16.3 1.5 3.9.sup.1) 0.7 1.0 2.68 0.5 3 P1 Ca(OH).sub.2 H.sub.3P NaO 9.3 PKSAB 73.5 21.7 1.0 2.6.sup.1) 0.4 0.8 1.34 0.5 4 P2 Ca(OH).sub.2 H.sub.3P NaO 9.5 PKSAB 73.9 21.0 1.0 2.5.sup.2) 0.5 1.1 1.53 0.5 5 P1 Ca(NH.sub.2SO H.sub.3P NaO 9.4 PKAB 68.5 21.8 8.5 0.5 0.7 1.34 0.5 .sup.1)Amidosulfonic acid; .sup.2)Acetic acid

TABLE-US-00003 TABLE 3 Pulverulent additives No. Polymer Metal salts Anion comp. Base/ acid pH Sequence Water (m %) Polymer (m %) Metal salt 1 (m %) Acid (m %) Anion comp. (m %) Base (m %) [00011]$\frac{\underset{i}{.Math.}.Math.z_{K,i}*n_{K,i}}{\underset{j}{.Math.}.Math.z_{S,j}*n_{S,j}}$ [00012]$\frac{\underset{l}{.Math.}.Math.z_{A,l}{n}_{A,l}}{\underset{j}{.Math.}.Math.z_{K,i}{n}_{K,i}}$ 1 P2 Ca(OH).sub.2 H.sub.3P NaO 10, PKSA 67.6 6.7 16.9.sup.1) 3.0 5.9 3.12 0.5 2 P1 Ca(OH).sub.2 H.sub.3P NaO 9.4 PKSA 69.9 6.5 16.6.sup.1) 2.9 4.1 2.68 0.5 3 P1 Ca(OH).sub.2 H.sub.3P NaO 9.3 PKSA 81.9 3.8 9.7.sup.1) 1.7 2.9 1.34 0.5 4 P2 Ca(OH).sub.2 H.sub.3P NaO 9.5 PKSA 80.8 4.0 9.2.sup.2) 1.8 4.2 1.53 0.5 5 P1 Ca(NH.sub.2SO.sub.3 H.sub.3P NaO 9.4 PKAB 83.4 12.1 1.7 2.8 1.34 0.5

[0345] The reference mortar is composed of anhydrite and 60% by weight of standard sand (DIN EN 196-1). As initiator, either 0.45% by weight of potassium sulfate or 0.90% by weight of Portland cement was added. The amount of anhydride is selected so as to give 100% by weight. The amount of water, based on the dry mortar, is 14.0% by weight, corresponding to a water-binder ratio of 0.35. For all of the experiments, the plasticizer content was selected such that the mortars attained a Hgermann cone slump of 2805 mm 5 minutes after addition of water.

[0346] The mortars are produced in accordance with DIN EN 196-1:2005 in a mortar mixer with a capacity of 5 l. For mixing up, water, plasticizer and anhydrite are introduced into the mixing vessel. Immediately thereafter the mixing operation is commenced, with the fluidizer at a low speed (140 rpm). After 30 seconds, the sand is added at a uniform rate over the course of 30 seconds (s) to the mixture. Thereafter the mixer is switched over to a higher speed (285 rpm) and mixing is continued for a further 30 s. The mixer is subsequently stopped for 90 s. During the first 30 s, the mortar sticking to the wall and to the lower part of the bowl is removed with a rubber scraper and put into the middle of the bowl. After the pause, the mortar is mixed for a further 60 s at the higher mixing speed. The total mixing time is 4 min.

[0347] Immediately after the end of the mixing operation, the slump of all the mortars is determined with the Hgermann cone, without any compaction energy being supplied, in accordance with the SVB Guidelines of the Deutscher Ausschuss fur Stahlbeton [German Reinforced Concrete Committee] [1]. The Hgermann cone (dtop=70 mm, p or 5 minutes after first contact between cement and water, the Hgermann cone is taken off, held over the slumping mortar for 30 seconds to allow for dripping, and then removed. As soon as the slump flow comes to a standstill, the diameter is determined, using a calliper gage, at two axes lying at right angles to one another, and the average is calculated. After the measurement, the sample is disposed of. At ages of 9, 29 and 59 minutes, the mortar which has remained in the mixing vessel is mixed up again with the mortar mixer for 10 s, in order to break down the resting structure, and this mortar is introduced into the Hgermann cone, and the slump is determined. [0348] [1] Deutscher Ausschuss fr Stahlbetonbau (Ed.): DAfStbRichtlinie Selbstverdichtender Beton [Self-compacting concrete guideline] (SVB Guideline). Berlin, 2003

Performance Examples

1) Self-Leveling Screed Based on Synthetic Anhydrite

Mixed Design:

[0349] 39.55% by weight synthetic anhydrite (Lanxess Anhydrittbinder CAB 30 (SO1281731), Stulln works)
0.45% by weight K.sub.2SO.sub.4
60.00% by weight standard sand
w/b=0.35
Target slump after 5 minutes: 281 cm

TABLE-US-00004 TABLE 4 Slump of self-leveling screed based on synthetic anhydrite Delta Metering Time of measurement 120 5 min Polymer Form [%] 5 min 10 min 30 min 60 min 120 min [cm] Melment Powder 0.35 27.5 27.1 25.7 24.5 23.2 4.3 F10 P1 Solution 0.07 28.4 27.8 25.7 23.8 22.4 6.0 P2 Powder 0.055 28.9 28.3 26.1 23.5 21.6 7.3 1 Powder 0.14 29.0 30.4 30.4 30.2 29.3 +0.3 2 Powder 0.26 27.7 30.2 30.5 30.2 30.3 +2.6 3 Powder 0.165 28.0 29.8 30.5 30.1 30.3 +2.3 4 Powder 0.08 28.0 28.7 27.6 27.7 27.4 0.6

2) Self-Leveling Screed Based on Natural Anhydrite

Mixed Design:

[0350] 39.10% by weight natural anhydrite (Knauf NAH Staub, Heidenheim works)
0.90% by weight OEM I 52.5 N (Milke)
60.00% by weight standard sand
w/b=0.35
Target slump after 5 minutes: 281 cm

TABLE-US-00005 TABLE 5 Slump of self-leveling screed based on natural anhydrite Metering [% by wt. Delta based on Slump in cm after (120 5 min) Polymer Form binder] 5 min 10 min 30 min 60 min 120 min [cm] P1 Solution 0.09 27.6 26.9 25.9 22.0 14.6 13.0 5 Powder 0.14 28.1 29.2 29.6 29.8 29.1 +1.0