Concrete flow improvers and water reducers

Abstract

The present invention relates to a process for preparing a poly(meth)acrylic acid, characterized in that a (meth)acrylic acid-containing process stream from (meth)acrolein synthesis is subjected to free-radical polymerization. The invention also relates to the esterification of the polymer obtained to give a homopolymer or copolymer ester, and to the use thereof as additive, flow improver and water reducer.

Claims

1. A process for preparing a poly(meth)acrylic acid, the process comprising: subjecting a process stream from (meth)acrolein synthesis containing between 8 and 50% by weight of (meth)acrylic acid, based on a total weight of the process stream, to free-radical polymerization in the presence of water formed in an oxidation reaction of the (meth)acrolein synthesis, thereby obtaining the poly(meth)acrylic acid.

2. The process according to claim 1, further comprising: subjecting the poly(meth)acrylic acid which is at least partially dissolved in water originating at least partially in the oxidation reaction of (meth)acrolein synthesis to further processing and/or functionalization, thereby obtaining a functionalized poly(meth)acrylic acid.

3. The process according to claim 2, wherein the functionalization is performed and is at least a partial polymer-analogous esterification.

4. The process according to claim 1, wherein a. the process stream contains one or more compounds selected from the group consisting of formaldehyde, acetic acid, maleic acid, maleic anhydride, terephthalic acid, formic acid, benzoic acid, (meth)acrolein, allyl alcohol, protoanemonin or a structural isomer thereof, terephthaldehyde, lactic acid, lactide, diformylfuran, hydroxycinnamic acid or a structural isomer thereof or dihydropyrancarbaldehyde and optionally a condensation or addition product, and an ester thereof, and/or b. the process stream contains a process stabilizer selected from the group consisting of a hydroquinone, a phenothiazine, a N-oxide-containing compound, and a combination thereof.

5. The process according to claim 1, wherein the process stream is subjected to free-radical polymerization in the presence of at least one chain transfer agent, at least one free-radical initiator, and/or at least one reducing agent.

6. The process according to claim 1, wherein the process stream contains TABLE-US-00011    8% to 40% by weight (meth)acrylic acid, 0.01% to 20% by weight formaldehyde, and  0.1% to 10% by weight each acetic acid and/or formic acid.

7. The process according to claim 1, wherein the process stream comprises: TABLE-US-00012 (meth)acrylic acid 8 to 35 % by weight, formaldehyde 0.01 to 5.0 % by weight, acetic acid 0 to 5.0 % by weight, maleic anhydride 0 to 3.0 % by weight, formic acid 0 to 5.0 % by weight, benzoic acid 0 to 2.0 % by weight, (meth)acrolein 0 to 2.0 % by weight, allyl alcohol 0 to 0.5 % by weight, hydroquinone 0 to 600 ppm by weight, protoanemonin 0 to 1000 ppm by weight, or a structural isomer thereof, and water.

8. The process according to claim 1, wherein the process stream contains an aldehyde or a hydrate thereof, and/or is subjected to a pretreatment.

9. The process according to claim 1, wherein the poly(meth)acrylic acid obtained is esterified in the presence of at least one secondary component or at least one conversion product thereof, and the secondary component and/or the conversion product thereof are at least partly thermally removed in the esterification.

10. The process according to claim 9, wherein the poly(meth)acrylic acid obtained is esterified with (methoxy)polyethylene glycol and/or with at least one alcohol having alkylene ether functionality.

11. The process according to claim 9, wherein the esterification is conducted with exclusion of a catalyst and/or within a temperature ranging from 120 to 250° C.

12. The process according to claim 2, wherein the poly(meth)acrylic acid and/or the functionalized poly(meth)acrylic acid are present at least partly in solution and/or formulated and/or isolated.

Description

EXAMPLES

(1) Characterization and Pretreatment of the Process Stream (Examples 1 to 7)

(2) In the examples which follow, an acrylic acid-containing process stream having a concentration of

(3) TABLE-US-00002 14.1% by weight acrylic acid, 2.9% by weight formaldehyde, 0.9% by weight acetic acid, 0.2% by weight formic acid, 0.1% by weight acrolein, 0.2% by weight benzoic acid, 129 ppm hydroquinone, 0.8% by weight maleic anhydride,

(4) based on the weight of the process stream, was used.

(5) The aldehydes present (primarily formaldehyde) in Examples 1-7 were precipitated with urea used in an equimolar amount and filtered off. Example 9 describes the production of a backbone using the unpretreated process stream containing acrylic acid.

(6) The pretreatment procedure is described by way of example below:

(7) 8651 g of the process stream containing acrylic acid were charged to a 10 l PE vessel and stirred with a magnetic stirrer. Then 495 g of urea are added and the system is stirred at room temperature for 24 hours. During this time, formaldehyde in solution in the process stream is precipitated in the form of a water-insoluble formaldehyde-urea polymer. After 24 hours, the resulting suspension is filtered off under reduced pressure with the aid of a suction flask via a filter paper (Macherey-Nagel, MN640w). The solid isolated by filtration is discarded; in the liquid phase, the formaldehyde fraction has reduced as a result of the pretreatment from 2.8% (determined by HPLC) to 460 ppm (determined photometrically).

Example 1

(8) A stirred 5 l jacketed glass reactor with a reflux condenser is initially charged with 400 g of deionized water and heated to 100° C.

(9) Thereafter, within 7 hours, 2624 g of a mixture of 2475 g of the acrylic acid-containing process stream and 149 g of methacrylic acid, and also 336 g of an aqueous 40% NaHSO.sub.3 solution, are metered in. At the same time, within 8 hours, 524 g of an aqueous 23% Na.sub.2S.sub.2O.sub.8 solution are metered in.

(10) After the end of the metered addition, the reaction mixture is kept at 100° C. for 1 hour.

(11) Subsequently, the reflux condenser is replaced by a Claisen head, and 2222 g of water are drawn off under a reduced pressure of 50 mbar.

(12) Then 2200 g of MPEG 1000 are added to the reactor and water is drawn off under reduced pressure for a further 4 hours. In the course of this, the temperature is increased up to 180° C.

(13) The reactor is cooled down to about 80° C. and emptied.

Example 2

(14) A stirred 5 l jacketed glass reactor with a reflux condenser is initially charged with 250 g of deionized water and heated to 100° C.

(15) Thereafter, within 2 hours, 190 g of an aqueous 40% NaHSO.sub.3 solution are metered in. At the same time, within 3 hours, 325 g of an aqueous 30% Na.sub.2S.sub.2O.sub.8 solution are metered in.

(16) 10 minutes after commencement of the metered addition of the NaHSO.sub.3 and the Na.sub.2S.sub.2O.sub.8, a further feed is started, which meters in 1641 g of a mixture of 1578 g of the acrylic acid-containing process stream and 93 g of methacrylic acid within 2 hours.

(17) After the metered additions have ended, the reflux condenser is replaced by a Claisen head, and 1293 g of water are drawn off under a reduced pressure of 50 mbar.

(18) Then 2750 g of MPEG 2000 are added to the reactor and water is drawn off under reduced pressure for a further 4 hours. In the course of this, the temperature is increased up to 180° C.

(19) The reactor is cooled down to about 80° C. and emptied.

Example 3

(20) A 500 ml round-bottom flask with a distillation column is initially charged with 110 g of MPEG1000, which are melted and heated to 150° C.

(21) Thereafter, 170 g of the acrylic acid-containing process stream are metered in within 3 hours. At the same time, within 4 hours, a solution of 1.32 g of TBPEH (tert-butyl peroxy-2-ethylhexanoate) in 262.68 g of toluene is metered in.

(22) During the metered addition, water and toluene are drawn off overhead.

(23) After the metered addition has ended, the temperature of the mixture is increased to 170° C. while continuing to draw off water and toluene.

(24) After a further 3 hours, the flask is cooled down to about 80° C. and emptied.

Example 4

(25) A stirred 1 l jacketed glass reactor with a reflux condenser is initially charged with 100 g of deionized water and heated to 100° C.

(26) Thereafter, within 7 hours, 630 g of a mixture of 592.7 g of the acrylic acid-containing process stream and 37.3 g of methacrylic acid, and also 126 g of an aqueous 40% NaHSO.sub.3 solution, are metered in. At the same time, within 8 hours, 131 g of an aqueous 23% Na.sub.2S.sub.2O.sub.8 solution are metered in.

(27) After the end of the metered addition, the reaction mixture is kept at 100° C. for another 1 hour.

(28) Of the polymer solution obtained, 200 g are initially charged in a 500 ml round-bottom flask with Claisen head, and 145 g of water are drawn off at a reduced pressure of about 50 mbar.

(29) Then 110 g of MPEG1000 are added, a reduced pressure of 50 mbar is applied and the mixture is heated up to 170° C. In the course of this, water is still being drawn off. 5 hours after addition of the MPEG1000, the mixture is cooled down to about 80° C. and the flask is emptied.

Example 5

(30) A stirred 5 l jacketed glass reactor with a reflux condenser is initially charged with 500 g of deionized water and heated to 100° C.

(31) Thereafter, within 3 hours, 500 g of an aqueous 30% Na.sub.2S.sub.2O.sub.8 solution are metered in. At the same time, within 2 hours, 420 g of an aqueous 40% NaHSO.sub.3 solution are metered in. Ten minutes after the start of these metered feeds, a further feed stream is commenced, in which within 1.5 hours 3270 g of a mixture of 3207 g of the acrylic acid-containing process stream and 192 g of methacrylic acid are metered in.

(32) After the end of the metered addition, the reaction mixture is kept at 100° C. for another 1 hour.

(33) Of the polymer solution obtained, 227 g are initially charged in a 1 l jacketed glass reactor with Claissen head. Then 330 g of MPEG 5000 are added, a reduced pressure of 50 mbar is applied and the mixture is heated to 175° C. In the course of this, water is removed by distillation.

(34) Four hours after addition of the MPEG 5000, the mixture is cooled down to about 80° C. and the flask is emptied.

Example 6

(35) A stirred 5 l jacketed glass reactor with a reflux condenser is initially charged with 500 g of deionized water and heated to 100° C.

(36) Thereafter, within 3 hours, 500 g of an aqueous 30% Na.sub.2S.sub.2O.sub.8 solution are metered in. At the same time, within 2 hours, 420 g of an aqueous 20% NaHSO.sub.3 solution are metered in. Ten minutes after the start of these metered feeds, a further feed stream is commenced, in which within 1.5 hours 3270 g of a mixture of 3208 g of the acrylic acid-containing process stream and 192 g of methacrylic acid are metered in.

(37) After the end of the metered addition, the reaction mixture is kept at 100° C. for another 1 hour.

(38) Of the polymer solution obtained, 530 g are initially charged in a 1 l jacketed glass reactor with Claissen head and 280 g of water are distilled off under a reduced pressure of about 50 mbar.

(39) Then 116 g of MPEG 1000 and 231 g of MPEG 2000 are added, a reduced pressure of 50 mbar is applied and the mixture is heated to 175° C. In the course of this, water is still being drawn off.

(40) Six hours after addition of the MPEG 1000 and MPEG 2000, the mixture is cooled down to about 80° C. and the flask is emptied.

Example 7

(41) A stirred 5 l jacketed glass reactor with a reflux condenser is initially charged with 500 g of deionized water and heated to 100° C.

(42) Thereafter, within 3 hours, 500 g of an aqueous 30% Na.sub.2S.sub.2O.sub.8 solution are metered in. At the same time, within 2 hours, 420 g of an aqueous 20% NaHSO.sub.3 solution are metered in. Ten minutes after the start of these metered feeds, a further feed stream is commenced, in which within 1.5 hours 3270 g of a mixture of 3208 g of the acrylic acid-containing process stream and 192 g of methacrylic acid are metered in.

(43) After the end of the metered addition, the reaction mixture is kept at 100° C. for another 1 hour.

(44) Of the polymer solution obtained, 250 g are initially charged in a 1 l jacketed glass reactor with Claissen head and 130 g of water are distilled off under a reduced pressure of about 50 mbar.

(45) Then 55 g of MPEG 1000 and 271 g of MPEG 5000 are added, a reduced pressure of 50 mbar is applied and the mixture is heated to 175° C. In the course of this, water is still being drawn off.

(46) Six hours after addition of the MPEG, the mixture is cooled down to about 80° C. and the flask is emptied.

Example 8

(47) Five mixtures were prepared from the polymer of Example 3 and five different commercially available product samples from different manufacturers and formulators, in each case in a ratio by mass of 1:1 (based on the solids content). An overview of the commercial product samples used, which may also consist of mixtures of different polymers, including characteristics available through analysis (NMR), is given in Table 2.

(48) TABLE-US-00003 TABLE 2 Commercial product samples used for comparison No. Field of use Composition.sup.1) 1 Concrete with high early strength Poly(methacrylic acid), about 80 wt % MPEG1000 2 Concrete with long retention of About 90 wt % PEG1000, a little PPG consistency 3 Concrete with moderate retention of Primarily PEG2000 (or longer), a little PPG consistency 4 Concrete with long retention of Poly(methacrylic acid), MPEG/PPG about 95/5 consistency (molar) 5 Concrete with long retention of Poly(acrylic/methacrylic acid), MPEG/PPG about 95/5 consistency (molar) .sup.1)based on solids

(49) The polymers prepared in the context of the invention and mixtures thereof with commercially available product samples were tested in performance studies with regard to their suitability and efficacy as concrete flow improvers. To assess the results of the performance studies, moreover, comparative measurements were carried out by the same methods on pure, commercially available product samples. All polymers and compositions were subjected to the same procedures.

(50) The test apparatus and metal moulds used are listed in Table 3, and the raw materials used in Table 4. The metal moulds used are also shown in FIG. 2.

(51) TABLE-US-00004 TABLE 3 Test apparatus and metal moulds Mortar mixer ToniMIX model 6214 Metal mould 1 conical frustocone according to standard DIN EN 12350-5 (dimensions reduced by a factor of 2.35) D = 85 mm, d = 55 mm, h = 85 mm Metal mould 2 conical frustocone according to standard DIN EN 12350-5 (dimensions reduced by a factor of 3.25) D = 62 mm, d = 40 mm, h = 62 mm

(52) TABLE-US-00005 TABLE 4 Raw materials used CEN standard sand according to DIN EN 196-1, Normsand GmbH Portland cement CEM | 52.5 N “White” EN 197-1, Lafarge Holcim Portland cement CEM | 42.5N DIN EN 197-1, Spenner Zement

(53) There follows a description of the performance studies and the results thereof.

Example 9

(54) A stirred 1 l jacketed glass reactor with a reflux condenser is initially charged with 100 g of deionized water and 0.15 g of FeSO.sub.4×7 H.sub.2O and this initial charge is heated to 100° C. Then, with stirring and over the course of 130 minutes, 80 g of a 20% solution of Brüggolit® FF6 in water are metered in. At the same, over the course of 190 minutes, 60 g of a 30% H.sub.2O.sub.2 solution are metered in. Ten minutes after the start of these metered feeds, a further feed stream is commenced, in which, over the course of 120 minutes, 651 g of a mixture of 663.5 g of the acrylic acid-containing process stream and 36.6 g of methacrylic acid are metered in. After the end of the metered addition, the reaction mixture is held at 100° C. fora further hour.

(55) The molecular weight of the backbone synthesized in this way is Mw=6000 g/mol.

(56) Performance Testing of Slump for Determination of the Flow-Improving Properties at Different PCE Concentrations

(57) 1350 g of standard sand are weighed out into the sand feed vessel of the mortar mixer, and 450 g of cement into the stirring bowl thereof.

(58) The flow improver is weighed into a beaker as an aqueous polymer solution and mixed with the amount of water required for attainment of a total amount of water of 225 g. The amount of the polymer solution (taking account of the concentration of the flow improver in the aqueous solution) is chosen according to the active ingredient concentration to be studied in the cement.

(59) After the aqueous polymer solution has been added to the cement present in the bowl, it is put into working position and the automatic EN196-1 program is started:

(60) The mixture is stirred at a rotational speed of 65 rpm for 30 sec, then the standard sand weighed out is metered into the mixing bowl over a period of 30 sec while continuing to stir.

(61) After the addition of the standard sand, stirring of the mortar mixture is continued at a rotational speed of 130 rpm for 30 sec.

(62) This is followed by a rest phase of 90 sec in which, during the first 30 sec, the inside of the mixing bowl is stripped by means of a scraper.

(63) The mixing operation is completed by stirring once again at 130 rpm for 60 sec.

(64) After the program has ended, the mortar is removed from the edge of the bowl with a scraper, mixed, and introduced into the metal mould 1 that has been moistened with demineralized water, which stands on a metal plate likewise moistened with demineralized water.

(65) By poking 10 times with a spatula, any trapped air is removed and the mortar is densified.

(66) Subsequently, the metal mould is rapidly lifted vertically upward, such that the mortar can flow outward.

(67) After the mortar has set and dried (generally the next day), the slump is measured in two directions and the mean is reported in millimetres.

(68) The results are collated in Tables 5 and 6.

(69) In comparison with the flow improvement obtained when using the commercial product specimens, a good flow-improving effect on the part of the polymers of the invention was found in portland cement CEM I 52.5 and CEM I 42.5, in some cases even at low concentrations and particularly in portland cement CEM I 42.5.

(70) Surprisingly it emerged, moreover, that the PCE according to Example 3, which exhibits only moderate flow improvement in CEM I 52.5 N, hardly reduces the improvement in flow in the mixture, and in some cases, indeed, showed synergistic effects.

(71) TABLE-US-00006 TABLE 5 Slumps in portland cement CEM I 52.5N “White”, DIN EN 197-1, Lafarge Holcim Slump (metal Concentration mould 1) Flow improver kg.sub.PCE/kg.sub.cement mm Example 1 0.20% 178 Example 1 0.30% 224 Example 1 0.40% 229 slight bleeding Example 1 0.50% 237 slight bleeding Example 1 0.75% 244 bleeding Example 2 0.20% 142 Example 2 0.30% 199 Example 3 0.20% 179 Example 3 0.30% 175 Example 3 0.50% 253 slight bleeding Example 4.sup.a) 0.10% 88 Example 4.sup.a) 0.20% 196 Example 4.sup.a) 0.50% 252 Example 4.sup.b) 0.10% 87 Example 4.sup.b) 0.20% 211 Example 4.sup.b) 0.50% 248 slight bleeding Example 5 0.10% 146 Example 5 0.20% 242 Example 5 0.30% 247 bleeding Example 5 0.40% 255 bleeding Example 6 0.10% 140 Example 6 0.20% 237 Example 6 0.30% 249 slight bleeding Example 7 0.10% 119 Example 7 0.20% 237 Example 7 0.30% 239 slight bleeding Product specimen 1 0.10% 90 Product specimen 1.sup.a) 0.20% 251 slight bleeding Product specimen 1.sup.b) 0.20% 257 slight bleeding Product specimen 1 0.30% 260 severe bleeding Product specimen 2 0.10% 104 Product specimen 2.sup.a) 0.20% 229 Product specimen 2.sup.b) 0.20% 229 Product specimen 2 0.30% 248 Product specimen 3 0.10% 110 Product specimen 3.sup.a) 0.20% 240 Product specimen 3.sup.b) 0.20% 249 slight bleeding Product specimen 3 0.30% 241 severe bleeding Product specimen 4 0.10% 99 Product specimen 4.sup.a) 0.20% 234 slight bleeding Product specimen 4.sup.b) 0.20% 234 slight bleeding Product specimen 4 0.30% 270 severe bleeding Product specimen 5 0.10% 142 Product specimen 5.sup.a) 0.20% 249 slight bleeding Product specimen 5.sup.b) 0.20% 268 slight bleeding Product specimen 5 0.30% 299 severe bleeding Example 3 - Product specimen 1.sup.c) 0.20% 248 minimal bleeding Example 3 - Product specimen 2.sup.c) 0.20% 201 minimal bleeding Example 3 - Product specimen 3.sup.c) 0.20% 227 minimal bleeding Example 3 - Product specimen 4.sup.c) 0.20% 232 minimal bleeding Example 3 - Product specimen 5.sup.c) 0.20% 252 minimal bleeding .sup.a), b)Two batches of the formulation designated were produced, and were both tested according to the procedure described. .sup.c)Mixtures in a ratio by mass (based on solids) of 1:1 in each case

(72) TABLE-US-00007 TABLE 6 Slumps in portland cement CEM I 42.5N, DIN EN 197-1, Spenner Zement Slump (metal Concentration mould 1) Flow improver kg.sub.PCE/kg.sub.cement mm Example 2 0.40% 151 slight bleeding, mortar not fully set Example 3 0.40% 245 Example 4.sup.a) 0.10% 96 Example 4.sup.a) 0.30% 136 Example 4.sup.a) 0.50% 201 Example 4.sup.a) 1.00% 214 Example 4.sup.b) 0.10% 108 Example 4.sup.b) 0.30% 197 Example 4.sup.b) 1.00% 217 bleeding Example 6 0.30% 148 Example 7 0.30% 147 Product specimen 1 0.50% 85 Product specimen 1 1.00% 188 Product specimen 2 0.30% 81 Product specimen 2 0.50% 241 Product specimen 3 0.30% 133 Product specimen 3 0.50% 249 Product specimen 4 0.10% 111 Product specimen 4 0.20% 214 slight bleeding Product specimen 4 0.50% 239 severe bleeding Product specimen 5 0.30% 153 Product specimen 5 0.50% 226 slight bleeding .sup.a), b)Two batches of the formulation designated were produced, and were both tested according to the procedure described.

(73) Performance Testing of the Long-Term Effect of the Flow-Improving Properties (Retention of Mortar Consistency)

(74) 1350 g of standard sand are weighed out into the sand feed vessel of the mortar mixer, and 450 g of cement into the stirring bowl thereof.

(75) The flow improver is weighed into a beaker as an aqueous polymer solution and mixed with the amount of water required for attainment of a total amount of water of 225 g. The amount of the polymer solution (taking account of the concentration of the flow improver in the aqueous solution) is chosen according to the active ingredient concentration to be examined in the cement.

(76) After the aqueous polymer solution has been added to the cement present in the bowl, it is put into working position and the automatic EN196-1 program is started:

(77) The mixture is stirred at a rotational speed of 65 rpm for 30 sec, then standard sand is metered into the mixing bowl over a period of 30 sec while continuing to stir.

(78) After the addition of the standard sand, stirring of the mortar mixture is continued at a rotational speed of 130 rpm for 30 sec.

(79) This is followed by a rest phase of 90 sec in which, during the first 30 sec, the inside of the mixing bowl was stripped by means of a scraper.

(80) The mixing operation is completed by stirring once again at 130 rpm for 60 sec.

(81) After the program has ended, the mortar is removed from the edge of the bowl with a scraper, mixed, and introduced into the metal mould 2 that has been moistened with demineralized water, which stands on a metal plate likewise moistened with demineralized water.

(82) By poking 10 times with a spatula, any trapped air was removed and the mortar was densified.

(83) Subsequently, the metal mould is rapidly lifted vertically upward, such that the mortar can flow outward.

(84) Thereafter, the mixing bowl is again put in working position and a rotational speed of 65 rpm is set by means of the manual program.

(85) After additional mixing times totalling 15 min, 30 min, 45 min, 60 min, 75 min and 90 min, the metal mould is filled again in each case as described above, trapped air is removed and then the metal mould is lifted rapidly vertically upward, such that the mortar can flow outward.

(86) After the mortar has set and dried (generally the next day), the different slumps are measured in two directions and the mean is reported in millimetres.

(87) The results from the first measurement are given the time 0, and then the subsequent measurements the additional total mixing times.

(88) The results are collated in Tables 7 and 8.

(89) TABLE-US-00008 TABLE 7 Slumps in portland cement CEM I 42.5N, DIN-EN 197-1, Spenner Zement as a function of time Example 3 Example 3 Example 4.sup.a) Example 4.sup.b) Concentration 0.75% 1.0% 0.5% 0.5% kg.sub.PCE/kg.sub.cement Additional Slump Slump Slump Slump mixing time (metal (metal (metal (metal min. mould 2) mould 2) mould 2) mould 2) mm mm mm mm 0 162 168 147.5 152.5 15 169 169 104 105 30 102 147 88 105 45 94 94 80 103 60 76 91 70 100 75 64 81 60 90 90 63 64 68 .sup.a), b)Two batches of the formulation designated were produced, and were both tested according to the procedure described.

(90) TABLE-US-00009 TABLE 8 Slumps in portland cement CEM I 52.5N “White”, DIN EN 197-1, Lafarge Holcim as a function of time Example 1 Example 3 Example 3 Example 3 Concentration 0.3% 0.2% 0.4% 1.0% kg.sub.PCE/kg.sub.cement Additional Slump Slump Slump Slump total mixing (metal (metal (metal (metal time min. mould 2) mould 2) mould 2) mould 2) mm mm mm mm 0 147 140 168 179 15 128 75 142 181 30 116 63 124 182 45 101 60 108 176 60 80 86 169 75 71 65 150 90 62 60 117 Example 4.sup.a) Example 4.sup.b) Example 4.sup.a) Example 4.sup.a) Concentration 0.2% 0.2% 0.3% 0.4% kg.sub.PCE/kg.sub.cement Additional Slump Slump Slump Slump total mixing (metal (metal (metal (metal time min. mould 2) mould 2) mould 2) mould 2) mm mm mm mm 0 140 150 165 168 15 75 100 144 150 30 63 70 100 122 45 60 60 74 88 60 62 65 75 60 60 Example 5 Example 6 Example 6 Example 6 Concentration 0.3% 0.2% 0.3% 0.4% kg.sub.PCE/kg.sub.cement Additional Slump Slump Slump Slump total mixing (metal (metal (metal (metal time min. mould 2) mould 2) mould 2) mould 2) mm mm mm mm 0 170 120 163 159 15 129 86 146 130 30 100 77 110 109 45 82 66 90 94 60 69 62 68 67 75 61 60 62 60 90 61 Example 7 Example 7 Example 7 Concentration 0.2% 0.3% 0.4% kg.sub.PCE/kg.sub.cement Additional Slump Slump Slump total mixing (metal (metal (metal time min. mould 2) mould 2) mould 2) mm mm mm 0 135 164 164 15 85 138 147 30 68 116 125 45 63 89 97 60 62 62 70 75 61 Example 5 Example 6 Example 6 Example 6 Concentration 0.3% 0.2% 0.3% 0.4% kg.sub.PCE/kg.sub.cement Additional Slump Slump Slump Slump total mixing (metal (metal (metal (metal time min. mould 2) mould 2) mould 2) mould 2) mm mm mm mm 0 170 120 163 159 15 129 86 146 130 30 100 77 110 109 45 82 66 90 94 60 69 62 68 67 75 61 60 62 60 90 61 .sup.a), b)Two batches of the formulation designated were produced, and were both tested according to the procedure described.

(91) Performance Testing of Slump for Determination of the Flow-Improving Properties at Varying Water/Cement Ratios

(92) 1350 g of standard sand are weighed out into the sand feed vessel of the mortar mixer, and 450 g of cement into the stirring bowl thereof.

(93) The flow improver is weighed into a beaker as an aqueous polymer solution and mixed with the amount of water required for attainment of the water/cement ratio (w/c ratio) to be examined. The amount of the polymer solution (taking account of the concentration of the flow improver in the aqueous solution) is chosen according to the active ingredient concentration to be examined in the cement.

(94) After the aqueous polymer solution has been added to the cement present in the bowl, it is put into working position and the automatic EN196-1 program is started:

(95) The mixture is stirred at a rotational speed of 65 rpm for 30 sec, then the standard sand weighed out is metered into the mixing bowl over a period of 30 sec while continuing to stir.

(96) After the addition of the standard sand, stirring of the mortar mixture is continued at a rotational speed of 130 rpm for 30 sec.

(97) This is followed by a rest phase of 90 sec in which, during the first 30 sec, the inside of the mixing bowl is stripped by means of a scraper.

(98) The mixing operation was completed by stirring once again at 130 rpm for 60 sec.

(99) After the program has ended, the mortar is removed from the edge of the bowl with a scraper, mixed, and introduced into the metal mould 1 that has been moistened with demineralized water, which stands on a metal plate likewise moistened with demineralized water.

(100) By poking 10 times with a spatula, any trapped air is removed and the mortar is densified.

(101) Subsequently, the metal mould is rapidly lifted vertically upward, such that the mortar can flow outward.

(102) After the mortar has set and dried (generally the next day), the slump is measured in two directions and the mean is reported in millimetres.

(103) The results are collated in Table 9. For comparison, the values for the slump without use of the flow improver are likewise reported.

(104) TABLE-US-00010 TABLE 9 Slumps in portland cement CEM I 52.5N “White”, DIN EN 197-1, Lafarge Holcim as a function of the water/cement ratio No flow improver Example 3 Example 4.sup.a) Example 4.sup.b) Concentration 0.0% 0.4% 0.2% 0.2% kg.sub.PCE/kg.sub.cement w/c ratio Slump Slump Slump Slump kg.sub.water/kg.sub.cement (metal (metal (metal (metal mould 1) mould 1) mould 1) mould 1) mm mm mm mm 0.30 — 84.5 — — 0.40 80.3 198.3 91.8 113.0 0.50 90.3 242.3 203.8 211.5 0.60 126.0 272.5 279.0 0.65 173.8 0.70 182.5 No flow improver Example 4.sup.a) Example 4.sup.b) Concentration 0.0% 0.3% 0.4% kg.sub.PCE/kg.sub.cement w/c ratio Slump Slump Slump kg.sub.water/kg.sub.cement (metal (metal (metal mould 1) mould 1) mould 1) mm mm mm 0.30 — 81.8 90.3 0.40 80.3 184.8 189.8 0.50 90.3 240.5 239.5 .sup.a), b)Two batches of the formulation designated were produced, and were both tested according to the procedure described.