Hydrocolloid Particle Suspension Useful as Rheological Modifier For Cementitious Applications, Use of Hydrocolloid Particle Suspension

Abstract

A hydrocolloid particle suspension comprises a concentration of at least 0.5 g/100 g of hydrocolloid particles, and a stabilizing additive containing at least one polyoxyalkylene moiety of 3 to 150 consecutive oxyalkylene units, wherein the at least one polyoxyalkylene moiety comprises at least 25 wt.-% of oxyethylene moieties, based on the total oxyalkylene moieties comprised in the stabilizing additive. The suspension contains less than 80 wt.-% of water and is useful as rheological modifier for cementitious applications. In the hydrocolloid particle suspension, the hydrocolloid particles are stabilized against premature swelling. The suspension exhibits adequate viscosity for ease of handling and dosage and is shelf-stable.

Claims

1. A hydrocolloid particle suspension, comprising a concentration of at least 0.5 g/100 g of hydrocolloid particles, and a stabilizing additive containing at least one polyoxyalkylene moiety of 3 to 150 consecutive oxyalkylene units, wherein the at least one polyoxyalkylene moiety comprises at least 25 wt.-% of oxyethylene moieties, based on the total oxyalkylene moieties comprised in the stabilizing additive, wherein the suspension contains less than 80 wt.-% of water, and wherein the suspension is useful as rheological modifier for cementitious applications.

2. The hydrocolloid particle suspension according to claim 1, wherein the hydrocolloid is selected from diutan gum, welan gum, xanthan gum, rhamsan gum, cellulose ethers, and mixtures thereof.

3. The hydrocolloid particle suspension according to claim 2, wherein the cellulose ether is selected from methylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, carboxymethylhydroxyethylcellulose, methylhydroxyethylcellulose, hydroxymethylethylcellulose, ethylcellulose, hydroxyethylpropylcellulose, and mixtures thereof.

4. The hydrocolloid particle suspension according to claim 2, wherein the hydrocolloid is diutan gum.

5. The hydrocolloid particle suspension according to claim 1, wherein the stabilizing additive is a polyoxyalkylene glycol.

6. The hydrocolloid particle suspension according to claim 1, wherein the stabilizing additive is a comb polymer having a carbon-chain backbone with anionic and/or anionogenic groups and polyoxyalkylene side chains.

7. The hydrocolloid particle suspension according to claim 6, wherein the proportion by weight of polyoxyalkylene moieties in the comb polymer is at least 55 wt.-%.

8. The hydrocolloid particle suspension according to claim 6, wherein the comb polymer has a charge density of 0.3 to 3.0 meq/g, assuming all anionogenic groups being fully ionized.

9. The hydrocolloid particle suspension according to claim 6, wherein the stabilizing additive is a comb polymer comprising structural units selected from formulae (Ia), (Ib), (Ic), and/or (Id), and structural units selected from formulae (IIa), (IIb), (IIc) and/or (IId): ##STR00012## wherein R.sup.1 is H, C.sub.1-C.sub.4 alkyl, CH, COOH or CH.sub.2COXR.sup.3A; X is NH(C.sub.nH.sub.2n1) or O(C.sub.n1H.sub.2n1) with n1=1, 2, 3 or 4, the nitrogen atom or the oxygen atom being bonded to the CO group; R.sup.2 is OM, PO.sub.3M.sub.2, or OPO.sub.3M.sub.2; or X is a chemical bond and R.sup.2 is OM; R.sup.3A is PO.sub.3M.sub.2, or OPO.sub.3M.sub.2; ##STR00013## wherein R.sup.3 is H or C.sub.1-C.sub.4 alkyl; n is 0, 1, 2, 3 or 4; R.sup.4 is PO.sub.3M.sub.2, or OPO.sub.3M.sub.2; ##STR00014## wherein R.sup.5 is H or C.sub.1-C.sub.4 alkyl, preferably H; Z is O or NR.sup.7; R.sup.7 is H, (C.sub.n1H.sub.2n1)OH, (C.sub.n1H.sub.2n1)PO.sub.3M.sub.2, (C.sub.n1H.sub.2n1)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, and n1 is 1, 2, 3 or 4; ##STR00015## wherein R.sup.6 is H or C.sub.1-C.sub.4 alkyl, preferably H; Q is NR.sup.7 or O; R.sup.7 is H, (C.sub.2n1H.sub.2n1)OH, (C.sub.n1H.sub.2n1)PO.sub.3M.sub.2, (C.sub.n1H.sub.2n1)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, n1 is 1, 2, 3 or 4; and ##STR00016## wherein R.sup.10, R.sup.11 and R.sup.12 independently of one another are H or C.sub.1-C.sub.4 alkyl; Z2 is O or S; E is C.sub.2-C.sub.6 alkylene, cyclohexylene, CH.sub.2-C.sub.6H.sub.10, 1,2-phenylene, 1,3-phenylene or 1,4-phenylene; G is O, NH or CONH; or E and G together are a chemical bond; A is C.sub.2-C.sub.5 alkylene or CH.sub.2CH(C.sub.6H.sub.5); n2 is 0, 1, 2, 3, 4 or 5; a is an integer from 3 to 150; R.sup.13 is H, an unbranched or branched C.sub.1-C.sub.4 alkyl group, CONH.sub.2 or COCH.sub.3; ##STR00017## wherein R.sup.16, R.sup.17 and R.sup.18 independently of one another are H or C.sub.1-C.sub.4 alkyl; E.sup.2 is C.sub.2-C.sub.6 alkylene, cyclohexylene, CH.sub.2-C.sub.6H.sub.10, 1,2-phenylene, 1,3-phenylene, or 1,4-phenylene, or is a chemical bond; A is C.sub.2-C.sub.5 alkylene or CH.sub.2CH(C.sub.6H.sub.5); n2 is 0, 1, 2, 3, 4 or 5; L is C.sub.2-C.sub.5 alkylene or CH.sub.2CH(C.sub.6H.sub.5); a is an integer from 3 to 150; d is an integer from 3 to 150; R.sup.19 is H or C.sub.1-C.sub.4 alkyl; and R.sup.20 is H or C.sub.1-C.sub.4 alkyl; ##STR00018## wherein R.sup.21, R.sup.22 and R.sup.23 independently are H or C.sub.1-C.sub.4 alkyl; W is O, NR.sup.25, or is N; V is 1 if W=O or NR.sup.25, and is 2 if W=N; A is C.sub.2-C.sub.5 alkylene or CH.sub.2CH(C.sub.6H.sub.5); a is an integer from 3 to 150; R.sup.24 is H or C.sub.1-C.sub.4 alkyl; R.sup.25 is H or C.sub.1-C.sub.4 alkyl; ##STR00019## wherein R.sup.6 is H or C.sub.1-C.sub.4 alkyl; Q is NR.sup.10, N or O; V is 1 if Q=O or NR.sup.10 and is 2 if Q=N; R.sup.10 is Hor C.sub.1-C.sub.4 alkyl; R.sup.24 is Hor C.sub.1-C.sub.4 alkyl; A is C.sub.2-C.sub.5 alkylene or CH.sub.2CH(C.sub.6H.sub.5); and a is an integer from 3 to 150; where each M independently is H or a cation equivalent.

10. The hydrocolloid particle suspension according to claim 1, additionally containing a structuring agent.

11. The hydrocolloid particle suspension according to claim 10, wherein the structuring agent is a cellulose insoluble fiber selected from the group of microfibrillated cellulose or nanocellulose.

12. The hydrocolloid particle suspension according to claim 1, any one of the preceding claims, additionally containing a defoaming agent.

13. The hydrocolloid particle suspension according to claim 12, wherein the defoaming agent is selected from polyoxyalkylene-based defoaming agents, phosphoric esters and silicon-based defoaming agents.

14. The hydrocolloid particle suspension according to claim 1, additionally containing a biocide.

15. The hydrocolloid particle suspension according to claim 1, exhibiting no sedimentation and/or floating-up upon storage for 2 months.

16. A method of modifying the rheology of a cementitious composition comprising adding a rheology-modifying amount of the hydrocolloid particle suspension of claim 1 to a cementitious composition.

17. The method of claim 16, wherein the modifying the rheology of the cementitious composition with the hydrocolloid particle suspension comprises modifying the viscosity of the cementitious composition.

18. The method of claim 16, wherein the modifying the rheology of the cementitious composition with the hydrocolloid particle suspension comprises enhancing the viscosity of the cementitious composition.

19. The hydrocolloid particle suspension according to claim 5, wherein the polyoxyalkylene glycol is polyoxyethylene glycol.

20. The hydrocolloid particle suspension of claim 9, wherein a. in formula (Ia), R.sup.1 is H or methyl; b. in formula (Ib), R.sup.3 is H or methyl; c. in formula (Ic), R.sup.5 is H; d. in formula (Id), R.sup.6 is H; e. in formulation (IIa), at least one of R.sup.10, R.sup.11, or R.sup.12 is independently H or methyl and A is C.sub.2-C.sub.3 alkylene; f. in formulation (IIb), at least one of R.sup.16, R.sup.17, or R.sup.18 is independently H, A is C.sub.2-C.sub.3 alkylene, and L is C.sub.2-C.sub.3 alkylene; g. in formulation (IIc), at least one of R.sup.21, R.sup.22, or R.sup.23 is independently H and A is C.sub.2-C.sub.3 alkylene; and h. in formula (IId), R.sup.6 is H and A is C.sub.2-C.sub.3 alkylene.

Description

EXAMPLES

[0220] The present invention is described in detail below with reference to the examples that follow.

Methods

[0221] Herein, the weight-average molecular weight values of the comb polymers were determined by gel permeation chromatography (GPC). As a stationary phase, a sequence of columns OH-Pak SB-G, OH-Pak SB 804 HQ and OH-Pak SB 802.5 HQ (available from Shodex) was used. As a mobile phase, an eluent of 80 vol.-% of an aqueous solution of HCO.sub.2NH.sub.4 (0.05 mol/L) and 20 vol.-% of methanol was used. The injection volume was 100 L at a flow rate of 0.5 mL/min. The molecular weight calibration was performed with polystyrene sulfonate standards for UV detectors (for polycondensates) and polyethylene oxide standards for RI detectors (for polycarboxylate ethers; both standards available from PSS Polymer Standards Service). The weight-average molecular weight determination of the polymers was performed by UV-detection at 254 nm.

[0222] Herein, the presence of sedimentation of the hydrocolloid particle suspension is determined by keeping a freshly-prepared hydrocolloid particle suspension in a graduated measuring cylinder. In the event that a clear supernatant has formed, its volume V.sub.sn is determined. The percentage of sedimentation is calculated according to the following formula, wherein V.sub.total denotes the total volume of the hydrocolloid particle suspension in the graduated measuring cylinder: [0223] (V.sub.sn:V.sub.total).Math.100%

[0224] Herein, the presence of floating-up of the hydrocolloid particle suspension is determined as described above, see sedimentation. In the event that a clear infranatant has formed, its volume V.sub.in is determined. The percentage of floating-up is calculated according to the following formula, wherein V.sub.total denotes the total volume of the hydrocolloid particle suspension in the graduated measuring cylinder: [0225] (V.sub.in:V.sub.total).Math.100%

[0226] Herein, the viscosity of the hydrocolloid particle suspension was determined using a Brookfield viscosimeter with spindle LVS61 at 20 C. and 12 rpm.

Materials

[0227] Hydrocolloid particle suspensions according to table 1 (all wt.-% expressed as active substance) were prepared according to the following procedure: The comb polymer and/or the polyoxyethylene glycol and/or -naphthalene sulfonate-formaldehyde condensate is placed in a beaker and stirred at the stirring rate as indicated in table 1 for 5 min. Subsequently, the nanocellulose, the defoaming agent and the biocide as indicated in table 1 are slowly added over a period of 5 min and the mixture is stirred until a homogeneous mixture is obtained. Then, to said homogeneous mixture, diutan gum powder is slowly added over a period of 5 min and the mixture is again stirred until a homogeneous mixture is obtained. The homogenous mixture is then transferred to a graduated measuring cylinder and the viscosity is determined. The stability (sedimentation and floating-up) and viscosity is monitored frequently.

TABLE-US-00003 TABLE 1 Viscosities and two-month-stability of hydrocolloid particle suspensions. # 1 # 2 # 3 # 4 # 5 # 6 # 7* # 8 # 9 Polycarboxylate ether .sup.[1] 41.5 41.7 41.1 41.7 0 0 0 0 41.0 [wt.-%] Polyarylether .sup.[2] 0 0 0 0 0 0 0 41.7 0 [wt.-%] PEG .sup.[3] [wt.-%] 0 0 0 0 88.5 0 0 0 0 BNS .sup.[4] [wt.-%] 0 0 0 0 0 37.2 0 0 0 SMF .sup.[5] [wt.-%] 0 0 0 0 0 0 40.2 0 0 Cellulose structuring 0.063 .sup.[6] 0 0.064 .sup.[6] 0.032 .sup.[6] 0.066 .sup.[6] 0.064 .sup.[7] 0.064 .sup.[7] 0.032 .sup.[7] 0.032 .sup.[7] agent[wt.-%] Defoaming agent .sup.[8] 0 2.0 0.5 3.3 3.3 1.0 3.3 3.3 3.3 [wt.%] Biocide .sup.[9] [wt.-%] 0 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 Diutan gum .sup.[10] 3.1 3.1 3.1 1.0 1.5 1.5 1.5 1.5 0 [wt.-%] Cellulose ether .sup.[11] 0 0 0 0 0 0 0 0 3.15 [wt.-%] Water .sup.[12] [wt.-%] 55.3 53.2 55.1 53.8 6.5 60.1 54.8 53.3 52.4 Stirring rate .sup.[13] 500 500 500 300 300 8000 300 300 300 [rpm] Initial viscosity .sup.[14] 3400 430 3100 885 360 1000 1450 405 1230 [mPa .Math. s] Stability after 2 months Floating-up [%] 27 0 0 0 0 18 20 0 0 Sedimentation [%] 0 80 0 0 0 0 0 0 0 .sup.[1] Comb copolymer (46% aqueous solution) containing acrylic acid and a PEG-macromonomer with an average molecular weight of 2400 g/mol and a charge density of 1 meq/g; available from Master Builders Solutions Deutschland GmbH. .sup.[2] (Phenol-PEG 2000)-formaldehyde-phenoxyethanolphosphat-polycondensate (48% aqueous solution) with a charge density of 0.9 meq/g; available from Master Builders Solutions Deutschland GmbH. .sup.[3] Polyoxyethylene glycol (PEG-600); available from Bernd Kraft GmbH .sup.[4] -Naphthalene sulfonate-formaldehyde (BNS) condensate (41% aqueous solution); available from Bozzetto Group .sup.[5] Sulfonated melamin-formaldehyde (SMF) condensate (45% aqueous solution); available from BASF Construction Additives GmbH .sup.[6] CELLULON R-88; available from CP Kelco .sup.[7] CELLULON L-88; available from CP Kelco .sup.[8] Polyethylenglykol-polypropylenglykol blockcopolymer; available from Dow Chemicals .sup.[9] Acticide MBS; available from THOR GmbH .sup.[10] Kelco-Crete DG-F; available from CP Kelco .sup.[11] Hydroxyethylcellulose .sup.[12] Including water introduced by any of [1], [2], [4], [5], [6], and [7] .sup.[13] stirring rate during the formulation process of the hydrocolloid suspensions .sup.[14] viscosity of the hydrocolloid particle suspensions determined at 20 C. (Brookfield viscosimeter with spindle LVS61, 12 rpm). * comparative example

[0228] The invention allows for preparing stable hydrocolloid particle suspensions. Therefore, it is possible to obtain formulations which can be properly handled and dosed in the respective areas of application. Using the hydrocolloid particle suspensions allows for a substantially homogenous density profile of the construction composition.