TWO COMPONENT SYNTHETIC WATER RETENTION AGENT AND RHEOLOGY MODIFIER FOR USE IN CEMENTS, MORTARS AND PLASTERS

Abstract

The present invention provides compositions useful as a replacement for cellulose ether in cement, plaster or mortar compositions comprising i) nonionic or substantially nonionic vinyl or acrylic brush polymers having pendant or side chain polyether groups, and having a relative weight average molecular weight of from 140,000 to 50,000,000 g/mole, and ii) aromatic cofactors containing one or more phenolic groups, such as catechol tannins, phenolic resins, polyphenolics, and napthhols or, in combination, one or more aromatic groups with at least one sulfur acid group, such as naphthalene sulfonate aldehyde condensate polymers, poly(styrene-co-styrene sulfonate) copolymers, and lignin sulfonates, preferably branched cofactors, including phenolic resins, aldehyde condensate polymers and lignin sulfonates. The compositions may comprise a dry powder blend of i) and ii), one dry powder of both i) and ii), or an aqueous mixture.

Claims

1. A composition useful as a replacement for cellulose ether in cement, plaster or mortar compositions comprising i) one or more nonionic or substantially nonionic vinyl or acrylic brush polymers having pendant or side chain polyether groups, and having a relative weight average molecular weight of from 140,000 to 50,000,000 g/mole, and ii) one or more aromatic cofactors containing one or more phenolic groups or, in combination, one or more aromatic groups with at least one sulfur acid group.

2. The composition as claimed in claim 1, wherein the weight ratio of the total amount of i) brush polymer solids to the total amount of ii) aromatic cofactor solids ranges from 1:0.5 to 1:10.

3. The composition as claimed in claim 1, wherein the ii) one or more aromatic cofactor is chosen from a naphthalene sulfonate aldehyde condensate polymer, a poly(styrene-co-styrene sulfonate) copolymer, lignin sulfonate, catechol tannins, phenolic resins, polyphenolics, napthhol, and mixtures thereof.

4. The composition as claimed in claim 1, wherein the i) one or more vinyl or acrylic brush polymers has a relative weight average molecular weight of from 150,000 to 5,000,000 g/mol.

5. The composition as claimed in claim 1, wherein the i) one or more vinyl or acrylic brush polymers has a pendant or side chain polyether group chosen from an alkoxy poly(ethylene glycol) group or a polyethylene glycol group.

6. The composition as claimed in claim 1, wherein the average number of ether groups in the pendant or side chain polyether groups of the i) one or more brush polymers ranges from 1.5 to 50 ether groups.

7. The composition as claimed in claim 1, wherein the i) one or more brush polymers is chosen from a polyethoxylated polyvinyl alcohol; a homopolymer of a macromonomer a) having a pendant or side chain polyether group, a copolymer of one or more macromonomers a) and one or more monomers b) chosen from lower alkyl (C.sub.1 to C.sub.4) alkyl (meth)acrylates, hydroxyalkyl (meth)acrylates, diethylenically unsaturated crosslinker monomers, and mixtures thereof.

8. The composition as claimed in claim 7, wherein at least one i) brush polymer is the copolymerization product of one or more macromonomers a) and one or more monomers b) and the total copolymerization product of monomers b) is present in the amount of from 0.1 to 40 wt. % of the i) brush polymer, based on the weight of monomers used to make the i) brush polymer.

9. The composition as claimed in claim 1, comprising any of: one dry powder; a dry powder blend of the i) one or more brush polymers as a powder and the ii) one or more aromatic cofactors as a powder; or, an aqueous mixture.

10. The composition as claimed in claim 1, further comprising a hydraulic cement or plaster, wherein the total amount of the ii) one or more aromatic cofactors, as solids, ranges from 0.1 to 10 wt. %, based on total cement solids.

11. A method for using the composition as claimed in claim 1, comprising any one of: a) adding to a wet hydraulic cement or plaster in the presence of shear the compositions in the form of a dry powder blend, one dry powder, an aqueous mixture, or mixtures thereof to form a cement, mortar or plaster, or; b) first adding the i) one or more brush polymers in any form to a wet hydraulic cement, mortar or plaster and then adding ii) one or more aromatic cofactors in the presence of shear to form a cement, mortar or plaster; and, then, applying the thus formed cement, mortar or plaster to a substrate.

Description

EXAMPLES

[0094] The following examples serve to illustrate the present invention. Unless otherwise indicated, the preparations and test procedures are carried out at ambient conditions of temperature and pressure.

Acrylic Brush Polymer Synthesis Process

[0095] All acrylic brush polymers in Examples 2 to 8 and 11-22 were synthesized in an aqueous solution shot polymerization process via free radical polymerization. Unless otherwise specified, a 1000 mL 4-neck round bottom reaction flask coupled with a thermo-couple, an overhead stirrer and a condenser was used for all polymer synthesis and a heating mantel was used to control reaction temperature. Unless stated otherwise, all chemicals used were from Sigma Aldrich (St. Louis, Mont.). All monomer reactants and a fixed amount of de-ionized water were charged first into the reactor. After the temperature rose to target temperature of 70° C., a controlled initial dosage of initiators was added and the temperature was held constant for two hours. After the two-hour polymerization, a second dosage of initiators was used to reduce the amount of residual monomers and the temperature was held constant for two hours. After the second two-hour reaction, the reactor was cooled down to near room temperature before taking the solution sample out of reactor for analysis and performance tests.

Polymer of Example 2 (See Table 1, Below)

[0096] A brush polymer was made via the Acrylic Brush Polymer Synthesis Process, above, wherein the reactants were 185 grams of de-ionized water and 10 grams of methoxypoly(ethylene glycol).sub.10.8 methacrylate (mPEGMA475) monomer all charged in the reaction flask. Temperature was set at 70±1° C. The initial dosage of initiator was 0.3 grams of 0.5 wt. % ammonium persulfate (APS) aqueous solution. The second dosage of initiator included 1 gram of 0.5 wt. % APS aqueous solution.

Polymer of Example 6 (See Table 1, Below)

[0097] A brush polymer was made via the Acrylic Brush Polymer Synthesis Process, above, in the same manner as the Polymer of Example 2, except the initial dosage of initiator was 2.0 grams of a 0.5 wt. % APS aqueous solution.

Polymer of Example 7 (See Table 1, Below)

[0098] A brush polymer was made via the Acrylic Brush Polymer Synthesis Process, above, in the same manner as the Polymer of Example 2, except 0.26 grams of ethylene glycol dimethacrylate (EGDMA) was added in the monomer mix before polymerization.

Polymer of Example 8 (See Table 1, Below)

[0099] A brush polymer was made via the Acrylic Brush Polymer Synthesis Process, above, wherein the reactants were 178 grams of de-ionized water and 21 grams of methoxy(polyethylene glycol).sub.17.05 methacrylate (mPEGMA750) monomer with 50wt % active all charged in the reaction flask. Temperature was set at 70±1 ° C. The initial dosage of initiator was 0.42 grams of 0.5 wt. % APS aqueous solution. The second dosage of initiator included 1.5 gram of 0.5 wt. % APS aqueous solution.

Ethoxylated PVOH Synthesis Process

[0100] All equipment was made of 316 stainless steel. Each reaction was run in a 600 mL reactor (Tube, about 5.12 cm diameter) and fitted with cooling coils and stirrer; two impeller sets which run at 800 RPM, a 98% hydrolyzed PVOH, having a weight average molecular weight of about 88,000 g/mol (Selvol™ 350 polymer, Sekisui Chemicals America, Dallas, Tex.). For each reaction, the catalyst (solid KOMe) was weighed out in a positive pressure glove box flushed with N.sub.2 gas, in an amount sufficient to give 300 ppm, based on solids at the end of reaction, or 0.1±0.05g, and was placed in the reactor. The indicated amount of the PVOH was added to the reactor; and the indicated amount anhydrous 2-methyl pyrrolidone (biological grade Sigma Aldrich, St. Louis, Mo.) was added to the reactor by syringe. The reactor was capped with a plastic beaker and moved to a reactor bay, wherein the beaker was removed and the reactor slipped over the impellor/cooling tube set as quickly as possible to reduce incoming water vapor from the atmosphere. The reactor was then padded and depressurized 5 times with N.sub.2 gas to remove air/water and all supply lines (N.sub.2 and ethylene oxide (EO)) were purged as per normal procedure. A stirrer was started (800 RPM) and the reactor temperature raised to 130° C. When the temperature was stable, an aliquot of EO was added until the reactor reached target reactor pressure (0.34 MPa). The EO was added to maintain but not exceed a maximum operating pressure of 0.39 MPa (56 psi) at a feed rate of about 25 g/hr. and the amount of EO metered in was totalized as reaction proceeds.

[0101] Once the target EO amount was added, the reaction was stopped and any remaining EO was “digested” while maintaining the reactor temperature at 130° C.; the total time from initial addition of EO to the start of digestion was about 8 hrs. and digestion was allowed to continue overnight at 130° C. The reaction was stopped when a computer monitored pressure gauge indicated a drop in pressure of less than 0.00689 MPa (1 psi) in a 60 minute period by dropping the reactor temperature to 60° C. after a further delay of 60 minutes.

[0102] After reaction, any excess EO was removed (about 24 hrs. after the reaction started) by sparging with N.sub.2 gas and the reactor was removed from the reactor bay.

[0103] In each example, the reaction product, a brown viscous (warm) liquid was removed from the reactor, which was washed with water. Some clear rubbery gel was observed at gas/liquid interface on reactor wall (˜1 g of gel).

[0104] In each example, about 20 mL of the resulting ethoxylated PVOH was separated from solvent and byproducts and purified by dialysis against de-ionized water by placing it in a dialysis membrane tube with a MW cutoff of 3,500 g/mol (Thermo-Fischer Scientific, Nazareth, Pa.); the dialysis tube was placed into a 3.7854 L (1 gallon) jar filled with deionized water. Fresh deionized water was exchanged twice a day over a 4-day dialysis period. After a 4-day dialysis, an ethoxylated PVOH aqueous solution was obtained.

[0105] The average number of ether groups in the pendant or side chain polyether groups of the ethoxylated PVOH brush polymers in each of Examples 22-25 was determined by mass balance. After the 4-day dialysis, a given sample of the aqueous solution was dried and the amount of reacted ethylene oxide was calculated by subtracting the amount corresponding to the polyvinyl alcohol in the sample. Thus, if the starting reactants consisted of 21 g of material, of which 20 g were ethylene oxide solids and 1 g was PVOH solids, and if a 10% weight fraction sample of the ethoxylated PVOH product weighs 1.5 g, then the product will have 10% of 1g or 0.1 g PVOH and the remainder or 1.4 g of reacted ethylene oxide; hence, adjusting for the proportion of hydroxyl groups in the PVOH, if 100% of the repeat units in the PVOH had a hydroxyl group, the ethoxylated PVOH would have an average of 14 ether groups per side chain (per hydroxyl group); if 50% of the repeat units in the PVOH had a hydroxyl group, the ethoxylated PVOH would have an average of 28 ether groups per side chain (per hydroxyl group). It is assumed that the dialysis membrane will not remove any PVOH reactant as the PVOH reactant weighs much more than 3,500 g/mole.

Polymer of Example 23

[0106] In this example, a brush polymer was made by the ethoxylated PVOH Synthesis Process, above, and the amount of PVOH placed in the reactor was 10 g as solids, the total amount of NMP added to the reactor was 190 g and the total target amount of EO supplied to the reactor was 100 g, thus giving 110 g product at 100% reaction. The reaction mixture if fully reacted would have given a copolymer wherein the average number of ether groups in the pendant or side chain polyether groups of the i) brush polymers is 10 ether groups, or, the weight ratio of ether group to PVOH reactants is 10:1; however, the observed product has an average number of 5 ether groups in the pendant or side chain polyether groups of the i) brush polymers by mass balance. The relative Mw of the resulting ethoxylated PVOH is reported in Table 1, below.

Polymer of Example 25

[0107] In this example, a brush polymer was made by the ethoxylated PVOH Synthesis Process, above, and the amount of PVOH placed in the reactor was 7.5 g as solids, the total amount of NMP added to the reactor was 143 g and the total target amount of EO supplied to the reactor was 150 g, thus giving 162.5 g product at 100% reaction. The reaction mixture if fully reacted would have given a copolymer wherein the average number of ether groups in the pendant or side chain polyether groups of the i) brush polymers is 20 ether groups, or, the weight ratio of ether group to PVOH reactants is 20:1; however, the observed product has an average number of 10 ether groups in the pendant or side chain polyether groups of the i) brush polymers. The relative Mw of the resulting ethoxylated PVOH is reported in Table 1, below.

Composition Solution Viscosity

[0108] Viscosity and shear thinning behavior of a 1.5 wt. % aqueous solution of the indicated brush polymer was measured at 25° C. on Anton Paar MCR 301 viscometer (Ashland, Va.) equipped with high-throughput automated system. The brush polymers were dissolved in the indicated concentrations and stirred until the solution became homogeneous in deionized (DI) water. Viscosity was collected at a shear range of 0.1 to 400 Hz. In Tables 1, 3 and 5, below, BNS refers to sodium naphthalene sulfonate formaldehyde condensate (Spectrum Chemicals, New Brunswick, N.J.), PSS refers to poly(styrenesulfonic acid sodium salt, 1,000 kg/mol manufacturer reported molecular weight, Sigma-Aldrich, St. Louis, Mo.) and lignin sulfonate refers to sodium salt of ligninsulfonate (Fisher Scientific, Waltham, Mass.).

[0109] As shown in the Table 1, below, the compositions having vinyl or acrylic brush polymers of the present invention and the aromatic cofactor of give room temperature shear viscosities as a 1.5 wt. % polymer aqueous solution that is comparable to that of cellulose ethers. A dramatic multiple factor viscosity increase resulted when an aromatic cofactor was added to an acrylic brush polymer. As shown in Examples 3, 4 and 5, it does not matter which aromatic cofactor gets used; however, the BNS is preferable. As shown in Example 7, a crosslinked brush polymer gives the best thickening results and is preferred.

Application Testing

[0110] All of the following tests were carried out based on the mortar formulation in Table 2, below. The mortar was made using the indicated materials by first preparing a drymix by combining all dry materials. After this, all the wet components like water, aqueous solutions of aromatic cofactor and brush polymers were combined in a mixing bowl and stirred until homogeneous. While mixing on mixing level one (low speed), the drymix was added to the mixing bowl and the resulting components were mixer for 30 seconds on level one and then for 30 seconds on level two (higher speed). The resulting wet mortar was allowed to rest for 90 seconds to dissolve soluble additives and was then mixed again for 60 seconds on level two.

TABLE-US-00001 TABLE 1 Solution Viscosity of Inventive Aqueous Compositions polymer viscosity viscosity Relative at at Mw 0.5 Hz 5.0 Hz Example Description (kg/mol) (cP).sup.2 (cP).sup.2   1* 1.5 wt. % HPMC.sup.1 (control) 710 10260 4270 solution   2* 1.5 wt. % mPEGMA475 2320 43 35 homopolymer solution  3 1.5 wt. % Example 2 polymer + 2320 7720 2190 3.75 wt. % BNS  4 1.5 wt. % Example 2 polymer + 2320 600 400 3.75 wt. % PSS  5 1.5 wt. % Example 2 polymer + 2320 400 300 3.75 wt. % lignin sulfonate  6 1.5 wt. % mPEGMA475 1440 4090 970 polymer + 3.75 wt. % BNS  7 1.5 wt. % crosslinked >5,000 9920 2500 mPEGMA475 polymer + 3.75 wt. % BNS  8 1.5 wt % mPEGMA750 1660 5600 1300 polymer + 3.75 wt. % BNS 11 and 12 mPEGMA500 homopolymer 2240 — — 14 mPEGMA2000 homopolymer 1070 — — 16 crosslinked mPEGMA475 >5,000 polymer from Example 7 17 mPEGMA475 homopolymer 230 19 80 wt. % mPEGMA500-20 150 — — wt. % MMA copolymer 20 94 wt. % mPEGMA500-6 1870 — — wt. % HEMA copolymer 21 85 wt. % mPEGMA500-15 1630 — — wt. % HEMA copolymer 22 72 wt. % mPEGMA500-28 350 — — wt. % HEMA copolymer 23 and 24 5EO average per side chain 300 — — ethoxylated PVOH 25 and 26 10EO average per side chain 720 — — ethoxylated PVOH .sup.1Methocel ™ F75M hydroxypropyl methylcellulose ether (The Dow Chemical Company, Midland, MI); .sup.2Viscosity is taken from 1.5 wt. % aq. Solution of just polymer* -; denotes Comparative Example.

[0111] As shown in Tables 3 and 5, below, the performance of the indicated compositions of the present invention the polymers of the present invention gave a mortar consistency and water retention similar to that of hydroxypropyl methyl cellulose ether at the same concentration. The cement setting rate is significantly less reduced with the inventive compositions than it is with the cellulose ether. The performance was tested in the mortar formulation for water retention capability (according to DIN 18555-7:1987-11, Beuth Verlag GmbH, Berlin, Del., 1987) and mortar consistency (according to CE17.3 DIN EN 196-3:2009-2, Beuth Verlag, 2009). Acceptable values for water retention capability are 90% or more, or, preferably, 95% or more. Acceptable values for mortar consistency are 90% or more, or, preferably, 95% or more. In the formulation, the order of addition and the liquid form or solid form of additives was not important.

TABLE-US-00002 TABLE 2 Mortar Formulation For Acrylic Brush Polymers Part (solids Material Identity wt. %) Cement Portland Type I cement 35.0 Sand Quartz Sand, 0.3 mm to 62.6 0.595 mm (mesh sieved) Vinyl acetate-ethylene Additive for cement-based  2.4 copolymer redispersible tile adhesives polymer powder Composition Details indicated in Table 3, See Table 3, below below

TABLE-US-00003 TABLE 3 Mortar Performance Water Mortar Example Description.sup.2 Retention Consistency  9* 0 wt. % of any polymer 73.3 <80 10* 0.4 wt. % polymer of Example 1 98.1 97.5 11A 0.4 wt. % mPEGMA500 polymer 98.4 100 of Example 11 + 0.4 wt. % BNS 12A 0.2 wt. % polymer of Example 11 + 98 100 0.2 wt. % BNS 13A 0.4 wt. % polymer of Example 6 + 97.5 98.4 0.4 wt. % BNS 14A 0.4 wt. % mPEGMA2000 polymer of 91 85 Example 14 + 1 wt. % BNS 15A 0.4 wt. % polymer of Example 7 + 98.7 95 1 wt. % BNS 16A 0.4 wt. % crosslinked mPEGMA475 100 97.5 polymer of Example 16 + 1 wt. % BNS 17A 0.4 wt. % mPEGMA475 polymer of 96.4 90 Example 17 + 1 wt. % PSS 18A 0.4 wt. % polymer of Example 2 + 98 95 0.2 wt. % PSS 19A 0.4 wt. % mPEGMA500-MMA 96.6 100 copolymer of Example 19 + 0.2 wt. % PSS 20A 0.4 wt % 94% mPEGMA500-HEMA 98.7 82.5 6% copolymer of Example 20 + 0.4 wt. % BNS 21A 0.4 wt. % 85% mPEGMA500- 98.1 82.5 15HEMA copolymer of Example 21 + 0.4 wt. % BNS 22A 0.4 wt. % 72% mPEGMA500- 98.8 80 28HEMA copolymer of Example 22 + 0.4 wt. % BNS .sup.1Methocel ™ F75M hydroxypropyl methylcellulose ether (The Dow Chemical Company, Midland, MI); .sup.2All wt. %s are of solids and are based on total cement solids. *denotes Comparative Example.

[0112] As shown in Table 3, above, all of the compositions of the present invention gave water retention values similar to that of hydroxypropyl methylcellulose ether (HPMC). The compositions of the present invention in Examples 11A-13A, 15A-16A, and 18A gave mortar consistency values similar to that of hydroxypropyl methylcellulose ether (HPMC); this shows that compositions comprising the brush polymers and cofactors of the present invention will develop good mortar consistency. Even the low molecular weight brush copolymer composition in Example 17A gives an acceptable water retention value. The Example 14A composition having a brush polymer with about 44 ether groups in the side chain macromonomer a) and about 44 ether groups on average in each side chain (it is a homopolymer) gives acceptable water retention; however, the average number of ether groups on the side chain of that brush polymer is higher than the preferred such average number.

Ethoxylated PVOH brush polymer Application Testing

[0113] In a CBTA mortar formulation using the indicated brush polymer and cofactor composition indicated from Table 5, below, and the mortar indicated in Table 4, below, the compositions of the present invention were mixed in the form of an aqueous solution of brush polymer cofactor composition with the indicated cement, sand and cement additive dry mix. Mortar water content varies from 20 to 21.5 wt. % of cement solids.

TABLE-US-00004 TABLE 4 Mortar Formulation For Vinyl Brush Polymers Parts (wt. % Material Identity solids) Cement Portland Type I cement 35.0 Sand Quartz Sand, 0.3 mm to 62.6 0.595 mm (mesh sieved) Vinyl acetate-ethylene Additive for cement-based  2.4 copolymer redispersible tile adhesives polymer powder Composition Details indicated in Table 5 See Table 5

TABLE-US-00005 TABLE 5 Mortar Performance Water Retention Shear Example Description.sup.2 (%) Stability  9* 0 wt. % polymer 73.3 <80 10* 0.4 wt. % Control F75M.sup.1 98.1 97.5 23A 0.2 wt. % 5EO ethoxylated PVOH + 99.3 97.5 0.2 wt. % BNS 24A 0.15 wt. % 5EO ethoxylated PVOH + 97.3 <80 0.25 wt. % BNS 25A 0.2 wt. % 10EO ethoxylated PVOH + 94.6 <80 0.2 wt. % BNS 26A 0.15 wt. % 10EO ethoxylated PVOH + 94.6 <80 0.25 wt. % BNS .sup.1Methocel ™ F75M hydroxypropyl methylcellulose ether (The Dow Chemical Company, Midland, MD; .sup.2All material amounts are solids, based on cement solids; *denotes Comparative Example.

[0114] As shown in Table 5, above, all of the mortar compositions having additives of the present invention gave water retention values similar to that of hydroxypropyl methylcellulose ether (HPMC). This shows that the ethoxylated PVOH of the present invention behaves like a cellulose ether when combined with an aromatic cofactor of the present invention.