Plasticizer having cationic side chains without polyether side chains

Abstract

The invention relates to the use of at least one comb polymer which includes side chains which have at least one cationic group, and does not include side chains having polyether groups, and which has a main chain which has carboxyl groups, as dispersant for hydraulically settable compositions. The invention also relates to hydraulically settable cement compositions, moldings, comb polymers and method for producing comb polymers.

Claims

1. A hydraulically settable composition comprising: a hydraulically settable binder comprising clay in an amount of 0.1 to 15 wt % relative to the total weight of the hydraulically settable binder, and at least one zwitterionic comb polymer in an amount of 0.01 to 5 wt %, relative to the total weight of the hydraulically settable binder, wherein the zwitterionic comb polymer has a main chain and consists of a) at least one acid unit A of formula (I): ##STR00004## wherein R.sup.1, R.sup.2 and R.sup.3, each independently represent H or an alkyl group having 1 to 5 carbon atoms, each R.sup.4 independently represents —COOM, —CH.sub.2COOM, —SO.sub.2—OM, —O—PO(OM).sub.2, or —PO(OM).sub.2; wherein M stands for H, an alkali metal, an alkaline earth metal, ammonium, an ammonium cation, an organic ammonium compound, or mixtures thereof; and b) at least one cationic structural unit K of formula (II) ##STR00005##  wherein R.sup.5 independently represents —CO—O—R′—, —NH—R′—, —CO—NH—R′—, —O—, R′, —O—R′—, or —R′—O—R′—, with R′ being a C.sub.1 to C.sub.20 alkylidene group, which can be branched or unbranched; R.sup.6 independently stands for a cationic group, and R.sup.7 independently stands for H or CH.sub.3.

2. The composition according to claim 1, comprising at least 15 wt % of a clay-containing gypsum, relative to the total weight of the composition.

3. The composition according to claim 1, wherein a total of structural units with side chains which have at least one cationic group, and structural units with carboxyl groups, is at least 75 mol %, relative to the total number of all monomeric structural units of the main chain of the comb polymer.

4. The composition according to claim 1, wherein a total of structural units with side chains which have at least one cationic group, and structural units with carboxyl groups, is at least 95 mol %, relative to the total number of all monomeric structural units of the main chain of the comb polymer.

5. The composition according to claim 1, wherein a total of structural units with side chains which have at least one cationic group, and structural units with carboxyl groups, is 100 mol %, relative to the total number of all monomeric structural units of the main chain of the comb polymer.

6. The composition according to claim 1, wherein the hydraulically settable composition contains up to 80 wt % water.

7. The composition according to claim 1, wherein the hydraulically settable composition contains up to 50 wt % water.

8. The composition according to claim 2, wherein the clay-containing gypsum contains less than 5 wt % water.

9. The composition according to claim 1, wherein the cationic group is a quaternary ammonium group.

10. The composition according to claim 1, wherein the cationic group has the formula —N.sup.+R.sup.8R.sup.9R.sup.10, in which R.sup.8, R.sup.9 and R.sup.10 each independently represent H, an aliphatic hydrocarbon residue having 1 to 20 C atoms, a cycloaliphatic hydrocarbon residue having 5 to 8 C atoms, or an aryl residue having 6 to 14 C atoms.

11. The composition according to claim 1, wherein the cationic group is a constituent of a monomeric structural unit, selected from the group consisting of [2-(acryloyloxy)-ethyl]-trimethylammonium chloride, [2-(acryloylamino)-ethyl]-trimethylammonium chloride, [2-(acryloyloxy)-ethyl]-trimethylammonium methosulfate, [2-(methacryloyloxy)-ethyl]-trimethylammonium chloride or -methosulfate, [3-(acryloylamino)-propyl]-trimethylammonium chloride, [3-(methacryloylamino)-propyl]-trimethylammonium chloride and diallyldimethylammonium chloride (DADMAC).

12. The composition according to claim 1, wherein the main chain is a polyacrylic acid, a polymethacrylic acid, or a copolymer of acrylic acid and methacrylic acid.

13. The composition according to claim 12, wherein the comb polymer comprises 5 to 100 mol % structural units having side chains which have at least one cationic group, and 10 to 95 mol % structural units having acid groups, each relative to the total number of all monomeric structural units in the main chain of the comb polymer.

14. The composition according to claim 1, wherein the hydraulically settable composition contains cement or gypsum.

15. The composition according to claim 1, wherein the hydraulically settable composition contains at least one additional dispersant.

16. The composition according to claim 15, wherein the at least one further dispersant is a polycarboxylate ether.

17. The composition according to claim 16, wherein a volume ratio of the polycarboxylate ether to the comb polymers is between 1:10 and 10:1.

18. The composition according to claim 16, wherein a volume ratio of polycarboxylate ether to the comb polymers is between 1:2 and 2:1.

19. The composition according to claim 1, wherein the at least one acid unit A is an acrylic acid unit or a salt thereof and/or a methacrylic acid unit or a salt thereof.

20. The composition according to claim 1, wherein the at least one acid unit A is a methacrylic acid unit or a salt thereof.

21. The composition according to claim 1, wherein the cationic group is a constituent of a monomeric structural unit, selected from [2-(acryloyloxy)-ethyl]-trimethylammonium chloride, [2-(acryloyloxy)-ethyl]-trimethylammonium methosulfate, [2-(methacryloyloxy)-ethyl]-trimethylammonium chloride, and [2-(methacryloyloxy)-ethyl]-trimethylammonium methosulfate.

22. The composition according to claim 1, wherein the at least one acid unit A is an acrylic acid unit or a salt thereof and/or a methacrylic acid unit or a salt thereof, and the cationic group is a constituent of a monomeric structural unit, selected from [2-(acryloyloxy)-ethyl]-trimethylammonium chloride, [2-(acryloyloxy)-ethyl]-trimethylammonium methosulfate, and [2-(methacryloyloxy)-ethyl]-trimethylammonium chloride, and [2-(methacryloyloxy)-ethyl]-trimethylammonium methosulfate.

23. A molding, obtainable by setting and curing a hydraulically settable composition according to claim 1.

Description

(1) FIG. 1 is a graphic illustration of the results for embodiment examples 5 to 19. For each example, the flow table spread in mm, as indicated in table 2, is represented.

(2) FIG. 2 is a graphic illustration of the results for embodiment examples 20 to 33. For each example, the flow table spread in mm, as indicated in table 3, is represented.

(3) FIG. 3 is a graphic illustration of the results for embodiment examples 34 to 46. For each example, the flow table spread in mm, as indicated in table 4, is represented. The terms “BASF 1” and BASF 2” refer to comb polymers V-1 and V-2 from the prior art.

(4) FIG. 4 is a graphic illustration of the results for embodiment examples 47 to 53. For each example, the flow table spread in mm, as indicated in table 5, is represented. The terms “BASF 1” and BASF 2” refer to comb polymers V-1 and V-2 from the prior art.

EMBODIMENT EXAMPLES

Examples 1 to 4: Production of the Polymers

(5) Polymer P-1 according to the invention was produced by placing 70 g water, 27.5 g [2-(methacryloyloxy)-ethyl]-trimethylammonium chloride (75% solution in water; trade name “Visiomer TMAEMC”, Evonik Industries, DE), 7.2 g acrylic acid, 1.5 g of a 10% aqueous solution of Fe(II)-SO.sub.4.7H.sub.2O and 1.5 g sodium hypophosphite in a reaction vessel equipped with a stirrer. 1.8 g of a 35% aqueous hydrogen peroxide and 1.6 g of a 5% aqueous solution of initiator (sodium hydroxymethyl sulfinate solution, trade name “Rongalit”, BASF, DE) was then added dropwise at a temperature of 25-50° C. over a period of 8 minutes with stirring. The reaction solution was cooled to avoid an increase in temperature to above 50° C., and once reaction was completed, stirring was continued for another 10 minutes to remove any residual peroxide.

(6) Polymers P-2 to P-4 were produced in the same manner as polymer P-1, but with different molar fractions of the monomers according to the data summarized in table 1.

(7) TABLE-US-00001 TABLE 1 Ex- am- Poly- Infeed ple mer Mol % Preparation (g) Infeed (g) Time 1 P-1 m = 50 70 g H.sub.2O, 1.5 g 1.8 g H.sub.2O.sub.2, 8 min n = 50 Fe(II), 1.5 g chain 1.6 g Rongalit transfer agent 2 P-2 m = 66 110 g H.sub.2O, 2.0 g 3.2 g H.sub.2O.sub.2, 10 min n = 34 Fe(II), 2.0 g chain 2.0 g Rongalit transfer agent 3 P-3 m = 34 70 g H.sub.2O, 2.0 g 3.2 g H.sub.2O.sub.2, 12 min n = 66 Fe(II), 2.0 g chain 2.0 g Rongalit transfer agent 4 P-4 m = 100 70 g H.sub.2O, 1.5 g 3.3 g H.sub.2O.sub.2, 10 min n = 0 Fe(II), 1.5 g chain 1.8 g Rongalit transfer agent m = molar fraction of cationic monomer; n = molar fraction of acrylic acid

Examples 5 to 33: Production of Settable Gypsum Compositions and Characterization of Flow Behavior

(8) The flow table spread (FTS), the start of hardening (SH) and the end of hardening (EH) of gypsum cakes were determined as follows. First, 140 g water was mixed with the comb polymer (plasticizer) and the additive. For this process, the quantity of comb polymer or plasticizer was adjusted beforehand with respect to the quantity of calcium sulfate. In the comparative tests, additives and/or comb polymers were omitted accordingly. 200 g calcium sulfate β-hemihydrate and 0.2 g calcium sulfate dihydrate were then sprinkled into the water over a period of 15 seconds, and the gypsum cake was allowed to soak for 15 seconds. This was then stirred vigorously by hand for 30 seconds. The mini-cone, having a diameter of 50 mm and a height of 51 mm, was filled, and after 75 seconds, the flow table spread (FTS) in millimeters was determined.

(9) The diameter of the resulting gypsum cake was measured as soon as no additional flow was observed. The diameter in mm was referred to as the flow table spread. The start of hardening and the end of hardening were determined using the knife cut method according to DIN EN 13279-2 and the thumbprint method. The start of hardening (SH) is reached when, after a knife cut is made through the gypsum cake, the edges of the cut no longer converge. The end of hardening (EH) is reached when water no longer emerges from the gypsum cake when approximately 5 kg of pressure is applied to the cake using a finger. To precisely and reproducibly adjust the clay content, pure calcium sulfate was mixed with an adjusted quantity of clay. Calcium sulfate-β-hemihydrate together with calcium sulfate dihydrate was used as the gypsum, and bentonite (Sigma-Aldrich Chemie GmbH, CH) was added.

(10) The test conditions and the results of two series of tests are summarized in tables 2 and 3. Non-inventive examples are categorized as “C” (comparative). For purposes of comparison and to test combinations, customary polycarboxyl ether (“PCE”; trade name Sika ViscoCrete G2; Sika, CH) and naphthalene sulfonate (trade name Flube 40, PCC Rokita SA, PL) were used.

(11) Examples 5 to 9 and 20 to 23 show comparative tests in which the comb polymers according to the invention were not added. Tests 5 to 7 and 20 to 22 show the results for gypsum compositions without clay content. A comparison of tests 6 and 8 shows the degree to which flowability is decreased in the presence of clay (example 8). Examples 10 to 13 show that the flowability of clay-containing gypsums can be increased substantially merely by adding the comb polymers according to the invention. The flowability is clearly similar to that of a comparable gypsum without clay content according to example 5. This indicates that the comb polymers according to the invention not only neutralize the clay, but have a plasticizing effect. When polycarboxylate ether is also added, flowability can be further improved to some extent, with levels being achieved in some cases that are within the range of the flowabilities of comparable compositions without clay but with polycarboxylate ethers (Examples 6, 16, 17 and 19). Tests 20 to 33 further demonstrate that flowability can be adjusted and optimized by selecting different comb polymers according to the invention on the basis of different clay contents. Depending on the desired application, the start of hardening and the end of hardening can also be varied and optimized.

Examples 34 to 53: Comparative Tests

(12) Comparative tests were conducted, in which the flow characteristics of gypsum compositions which contain the comb polymers according to the invention or comb polymers according to the prior art of EP 2 463 317 A1 were analyzed. EP 2 463 317 A1 discloses comb polymers which comprise side chains having a cationic group and side chains having polyether groups. For the comparative tests, cationic comb polymers C-1 and C-2 were produced according to the method used in synthesis examples 2 and 3 of EP 2 463 317 A1. The flow characteristics of these comb polymers and of comb polymers P-1 to P-4 according to the invention, from embodiment examples 1 to 4, were then analyzed. In this analysis, flow table spread, start of hardening and end of hardening were determined, as described above for examples 5 to 33.

(13) In a series of tests conducted on embodiment examples 34 to 46, the same volume fractions for the comb polymers were used in each case. The results are summarized in table 4 and illustrated graphically in FIG. 3. The results show that the properties of the comb polymers according to the invention without polyether side chains are substantially improved over those of similar comb polymers having polyether side chains. The gypsum compositions with comb polymers according to the invention have a substantially higher flow table spread. The start of hardening (SH) and the end of hardening (EH) are substantially higher for the comb polymers according to the invention. Overall, the comparative tests show that the properties of the comb polymers without polyether side chains as plasticizers and dispersants are substantially better than those of known comb polymers with polyether side chains.

(14) In a further series of tests conducted on embodiment examples 47 to 53, different volume ratios of the comb polymers according to the invention were used. The gypsum compositions contained customary polycarboxylate ethers (PCE). The results are summarized in table 5, and are illustrated graphically in FIG. 4. The results show that even much smaller quantities of the comb polymers according to the invention are sufficient to achieve a plasticizing effect corresponding to that of comb polymer C-1 or C-2 of EP 2 463 317 A1. Therefore, substantially smaller quantities of the comb polymer according to the invention are sufficient to replace cationic comb polymers from the prior art.

(15) TABLE-US-00002 TABLE 2 Additive for Adsorption Flow β- Polymer on Clay table Bentonite Hemihydrate Add. Add. spread SH EH Example Cat. % % Name % Name % [mm] [h:min:s] [h:min:s] Name 5 C 0.0% 100.0% — 0.00 — 0.00 140 00:02:20 00:06:20 — 6 C 0.0% 100.0% — 0.00 PCE 0.20 213 00:04:05 00:12:30 PCE 7 C 0.0% 100.0% — 0.00 Naph 0.20 173 00:02:45 00:06:55 Naph 8 C 1.0% 99.0% — 0.00 PCE 0.20 123 00:02:25 00:08:55 PCE 9 C 1.0% 99.0% — 0.00 Naph 0.20 166 00:02:30 00:07:10 Naph 10 1.0% 99.0% — 0.00 P-1 0.20 182 00:06:15 00:15:10 P-1 11 1.0% 99.0% — 0.00 P-2 0.20 158 00:02:45 00:14:15 P-2 12 1.0% 99.0% — 0.00 P-3 0.20 142 00:06:30 00:16:00 P-3 13 1.0% 99.0% — 0.00 P-4 0.20 150 00:02:45 00:07:05 P-4 14 C 1.0% 99.0% PCE 0.20 — 0.20 122 00:02:30 00:08:20 PCE 15 C 1.0% 99.0% 0.00 Naph 0.20 166 00:02:30 00:07:10 Naph 16 1.0% 99.0% PCE 0.20 P-1 0.20 196 00:11:30 00:20:10 PCE + P-1 17 1.0% 99.0% PCE 0.20 P-2 0.20 203 00:04:25 00:11:25 PCE + P-2 18 1.0% 99.0% PCE 0.20 P-3 0.20 139 00:08:55 00:21:00 PCE + P-3 19 1.0% 99.0% PCE 0.20 P-4 0.20 192 00:03:30 00:10:10 PCE + P-4 Naph = naphthalene sulfonate; PCE = polycarboxylate ether

(16) TABLE-US-00003 TABLE 3 Additive for Adsorption Flow β- Polymer on Clay table Bentonite Hemihydrate Add. Add. spread SH EH Example Cat. % % Type % Type % [mm] [h:min:s] [h:min:s] 20 C 0.0% 100.0% 0.00 — 0.00 140 00:02:20 00:06:20 21 C 0.0% 100.0% 0.00 PCE 0.20 213 00:04:05 00:12:30 22 C 0.0% 100.0% 0.00 Naph 0.20 173 00:02:45 00:06:55 23 C 1.0% 99.0% PCE 0.20 PCE 0.00 122 00:02:30 00:08:20 24 1.0% 99.0% PCE 0.20 P-1 0.20 196 00:11:30 00:20:10 (0.2%) 25 1.0% 99.0% PCE 0.20 P-1 0.15 182 00:06:20 00:14:10 (0.15%) 26 1.0% 99.0% PCE 0.20 P-1 0.10 169 00:03:55 00:11:15 (0.1%) 27 1.0% 99.0% PCE 0.20 P-2 0.20 200 00:04:30 00:11:50 (0.2%) 28 1.0% 99.0% PCE 0.20 P-2 0.10 180 00:03:30 00:09:40 (0.1%) 29 1.0% 99.0% PCE 0.20 P-2 0.05 153 00:03:00 00:08:45 (0.05%) 30 3.0% 97.0% PCE 0.20 P-1 0.20 118 00:03:25 00:10:45 (0.2%) 31 3.0% 97.0% PCE 0.20 P-1 0.40 163 00:18:05 00:29:00 (0.4%) 32 3.0% 97.0% PCE 0.20 P-2 0.20 126 00:03:00 00:08:20 (0.2%) 33 3.0% 97.0% PCE 0.20 P-2 0.40 189 00:03:50 00:10:40 (0.4%) Naph = naphthalene sulfonate; PCE = polycarboxylate ether

(17) TABLE-US-00004 TABLE 4 Additive for Adsorption on Flow β- Polymer Clay table Bentonite Hemihydrate Add. Add. spread SH EH Example Cat. % % Type % Type % [mm] [h:min:s] [h:min:s] 34 C 1.0% 99.0% PCE 0.20 0.00 164 00:02:55 00:09:30 35 C 1.0% 99.0% 0.00 C-1 0.20 162 00:02:20 00:07:05 36 C 1.0% 99.0% 0.00 C-2 0.20 128 00:02:10 00:06:40 37 1.0% 99.0% 0.00 P-1 0.20 206 00:09:50 00:20:00 38 1.0% 99.0% 0.00 P-2 0.20 208 00:04:50 00:10:15 39 1.0% 99.0% 0.00 P-3 0.20 182 00:09:40 00:22:30 40 1.0% 99.0% 0.00 P-4 0.20 196 00:02:40 00:07:55 41 C 1.0% 99.0% PCE 0.20 C-1 0.20 206 00:03:55 00:12:00 42 C 1.0% 99.0% PCE 0.20 C-2 0.20 222 00:04:10 00:11:40 43 1.0% 99.0% PCE 0.20 P-1 0.20 220 00:15:20 00:26:00 44 1.0% 99.0% PCE 0.20 P-2 0.20 240 00:08:25 00:19:00 45 1.0% 99.0% PCE 0.20 P-3 0.20 187 00:13:55 00:31:00 46 1.0% 99.0% PCE 0.20 P-4 0.20 229 00:05:25 00:12:30

(18) TABLE-US-00005 TABLE 5 Additive for Adsorption on Flow β- Polymer Clay table Bentonite Hemihydrate Add. Add. spread SH EH Example Cat. % % Type % Type % [mm] [h:min:] [h:min:] 47 C 1.0% 99.0% PCE 0.20 — — 164 00:02:55 00:09:30 48 C 1.0% 99.0% PCE 0.20 C-1 0.200 212 00:04:00 00:12:10 49 C 1.0% 99.0% PCE 0.20 C-2 0.200 217 00:04:25 00:12:15 50 1.0% 99.0% PCE 0.20 P-1 0.150 217 00:09:00 00:18:00 51 1.0% 99.0% PCE 0.20 P-1 0.120 200 00:05:20 00:12:50 52 1.0% 99.0% PCE 0.20 P-1 0.135 209 00:05:45 00:14:00 53 1.0% 99.0% PCE 0.20 P-2 0.120 218 00:04:30 00:11:55