EMULSION POLYMER TWO-COMPONENT COMPOSITIONS FOR FAST CURING CEMENTITIOUS WATERPROOFING MEMBRANES

Abstract

The present invention provides two-component compositions comprising a component A) one or more acrylic aqueous emulsion copolymer having a measured glass transition temperature (T.sub.g) of from −20 to 0° C. and which is the copolymerization product of (i) from 60 to 89.9 wt. % of one or more nonionic (meth)acrylic monomers, (ii) from 10 to 40 wt. % of one or more vinyl aromatic monomers, (iii) from 0.1 to 2.0 wt. % of one or more monomers chosen from itaconic acid, methacrylic acid, amides of a,β-unsaturated C.sub.3 to C.sub.6 carboxylic acids, and mixtures thereof, all wt. %s of monomers based on the total monomer solids, wherein the aqueous emulsion copolymer has at least one residue of an ascorbic acid reducing agent or is the copolymerization product of a monomer (iii) comprising itaconic acid, and, a separate component B) comprising a fast curing dry mix powder composition of a hydraulic cement and a high alumina content cement.

Claims

1. A two-component composition for making a waterproofing membrane comprising as one component A) one or more aqueous emulsion copolymer having a measured glass transition temperature (T.sub.g) of from −40 to 0° C. and comprising the residue of a reducing agent, and, as a separate component B) a fast curing dry mix powder composition of a hydraulic cement and a high alumina content cement, wherein the aqueous emulsion copolymer in component A) is the copolymerization product of (i) from 60 to 89.9 wt. % of one or more nonionic (meth)acrylic monomers, (ii) from 10 to 40 wt. % of one or more vinyl aromatic monomers, and (iii) from 0.1 to 2.0 wt. % of one or more monomers chosen from itaconic acid, methacrylic acid, amides of a,β-unsaturated C.sub.3 to C.sub.6 carboxylic acids, and mixtures thereof, all wt. %s of monomers based on total monomer solids, with the proviso that the aqueous emulsion copolymer has at least one residue of an ascorbic acid reducing agent or is the copolymerization product of a monomer (iii) comprising a mixture of itaconic acid and an amide of a,β-unsaturated C.sub.3 to C.sub.6 carboxylic acid.

2. The composition as claimed in claim 1 wherein, when the aqueous emulsion copolymer of component A) is the copolymerization product of a monomer (iii) including the one or more amides of a,β-unsaturated C.sub.3 to C.sub.6 carboxylic acids, it further comprises the copolymerization product of (iv) one or more hydroxyalkyl (meth)acrylate.

3. The composition as claimed in claim 2, wherein the aqueous emulsion copolymer of component A) comprises the copolymerization product of from 0.1 to 1.5 wt. % of (iv) one or more hydroxyalkyl (meth)acrylate, all wt. %s of monomers based on total monomer solids.

4. The composition as claimed in claim 1, wherein the aqueous emulsion copolymer of component A) comprises the copolymerization product of (i) one or more nonionic (meth)acrylic monomers chosen from butyl acrylate, ethyl acrylate, and 2-ethylhexyl acrylate.

5. The composition as claimed in claim 1, wherein the two-component composition comprises from 10 to 60 wt. % as solids of the one or more aqueous emulsion copolymer of component A), based on the total solids content of the composition.

6. The composition as claimed in claim 1, wherein the reducing agent residue in the aqueous emulsion copolymer of component A) is present in amounts of from 0.1 to 0.5 wt. %, based on the total monomer solids used to make the aqueous emulsion copolymer.

7. The composition as claimed in claim 1, wherein the fast curing dry mix powder composition component B) comprises from 1 to 35 wt. % of high alumina content cement, based on total solids in component B).

8. The composition as claimed in claim 1, wherein the fast curing dry mix powder composition component B) comprises from 0 to 15 wt. % calcium sulfate, based on the total solids in component B).

9. The composition as claimed in claim 1, wherein the fast curing dry mix powder composition component B) comprises from 15 to 65 wt. % hydraulic cement, all wt. %s based on the total solids in component B).

10. The composition as claimed in claim 1, wherein the fast curing dry mix powder composition component B) comprises from 30 to 85 wt. % of one or more non-cementitious filler.

Description

EXAMPLES

[0052] The following examples are provided for illustrative purposes only and are not intended to limit the scope of the claims that follow.

[0053] Unless otherwise indicated, all parts and percentages are by weight, all temperatures are at room temperature (RT), and all pressures are at standard pressure.

Synthesis Example 1

Making the Aqueous Emulsion Copolymer of Example 1

[0054] A multi-neck reaction flask was charged with 290 g deionized (DI) water, 1.9 g of FES 993 (sodium lauryl ethoxy (EO) ether sulfate, 12 EO Units, BASF SE, Ludwigshafen, Germany), and 2.2 g Tergitol 15-S-40 (secondary alcohol ethoxylate—40 EO units, 35 wt. % in water, The Dow Chemical Company, Midland, Mich.). The necks were set up to accommodate an overhead mechanical stirrer, a nitrogen inlet, a thermocouple, a condenser, and two inlets for the addition of reactants via pump. A monomer emulsion of 225 g water, 17 g FES 993, 9.3 g Tergitol 15-S-40, 690 g butyl acrylate (BA), 280 g styrene (STY), 19 g acrylamide (AM), and 5 g 2-hydroxyethyl methacrylate (HEMA) was prepared. The reaction flask was heated to 88 to 94° C. before 29 g of a 9% sodium bicarbonate solution, 50 g of monomer emulsion, and 10.5 g of 10% sodium persulfate solution in water were added to the flask. After the resulting exotherm, the monomer emulsion and 78 g of a 4 wt. % solution of sodium persulfate in water were added over a period of 180 to 240 min while maintaining a temperature of 87 to 92° C. After the end of feeds, the reaction was held at 80 to 90° C. for approximately 30 min before being cooled to 70 to 77° C. Then 5 g of 3.3 wt. % t-butyl hydrogen peroxide solution in water and 6 g of 3 wt. % sodium bisulfite solution in water were added to the flask. Then 24 g each of 8 wt. % t-butyl hydrogen peroxide and 19 wt. % isoascorbic acid solutions in water were added via pump over 1 hour (h). The reaction was cooled to 60° C., and 9 g each of 9 wt. % t-butyl hydrogen peroxide and 9 wt. % isoascorbic acid solutions in water were added before holding the reaction at 55-70° C. for a minimum of 30 min. The product of the reaction had solids content ranging from 55 to 58% and a pH below 5

Synthesis Example 2

Making the Aqueous Emulsion Copolymer of Example 2

[0055] The copolymerization was run as in Synthesis Example 1 except that the acrylamide level in the monomer emulsion was cut in half and 10 g of itaconic acid was added to make up for the reduced level of acrylamide. Additionally, the solutions of isoascorbic acid were replaced with a 12 wt. % solution in water of sodium metabisulfite, Brüggemann Chemical, Heilbronn, Germany). The product of the reaction had solids content ranging from 55 to 58% and a pH below 5.

Synthesis Example 3

Making the Aqueous Emulsion Copolymer of Example 3

[0056] The copolymerization was run as in Synthesis Example 1 except that in the monomer emulsion, the level of BA was increased to 820 g while the level of STY was decreased to 150 g.

Comparative Synthesis Example 1

Making the Aqueous Emulsion Copolymer of Comparative Example 1

[0057] The copolymer was made in the manner disclosed Synthesis Example 1, except that the solutions of isoascorbic acid were replaced with a 20 wt. % solution in water of sodium bisulfite. The product of the reaction has solids content ranging from 55 to 58% and a pH below 7.

Comparative Example 2

Aqueous Emulsion Copolymer

[0058] The aqueous emulsion copolymer having the monomer mixture and reagents as listed in Table 2, below, was made by single stage gradual addition emulsion polymerization in the presence of an acrylic emulsion polymer seed, an anionic surfactant and a 15% sodium persulfate solution in water. The emulsion copolymer was cooled to 60 to 70° C. and then residual monomers were chased through the addition of an aqueous solution containing 3 wt. % t-butyl hydrogen peroxide and 0.5 wt. % hydrogen peroxide and, in parallel, a 4 wt. % solution of isoascorbic acid to the flask over a period of 0.75-1 h. The final mixture had solids content ranging from 50 to 55% and a pH of above 5.

[0059] Table 1, below, discloses the fast curing dry mix powder composition formulations used in the Examples.

TABLE-US-00001 TABLE 1 Fast Cure Dry Mix Formulation FAST DRY MIX Ingredients Wt. % % Ordinary Portland Cement (OPC CEM I 42.5R.sup.1) 25.30 Calcium Aluminate Cement (CAC Ternal.sup.TM,2 RG) 12.00 Snow White.sup.TM,3 filler (CaSO.sub.4) 2.70 Quarzsand.sup.TM,4 F32 (average PS 0.24 mm) 36.40 Quarzsand.sup.TM,4 F36 (average PS 0.16 mm) 23.45 WALOCEL.sup.TM,5 MKX 6000 PF01 .sup.1OPC CEM I 42.5R (From Heidelberger, Germany); OPC CEM I = Ordinary Portland Cement type I Comprising Portland Cement and up to 5% of minor additional constituents. 42.5R-Compressive strength >42.5 after 28 d; .sup.2CAC Ternal RG Kerneos SA, France (Calcium Aluminate Cement clinker >99.5 wt. %); .sup.3Snow White Filler, USG, CaSO4 >97.68%; .sup.4Quarzsand FH 32/FH36, Quarzwerke GmbH, Germany; .sup.5Walocel MKX 6000 PF 01 Hydroxyethyl methyl cellulose (HEMC) thickener powder giving a viscosity of 60000 cps (Haake, 2.55 reciprocal seconds) in a 2 wt. % solution in water at room temperature (Dow Chemical, Midland MI); 6. Arbocel PWC 500, J. RETTENMAIER & SÖHNE GMBH + CO, Germany. Natural cellulose fibers; 7. Finntalc M15, MONDO MINERALS B.V. Netherlands, Mg-silicate.

TABLE-US-00002 TABLE 2 Emulsion Polymer Compositions Emulsion Polymer Comp Ex. Comp Ex. Example 1 Example 2 Example Materials 1 (wt. %) 2 (wt. %) (wt. %) (wt. %) 3 (wt. %) Monomers Butyl acrylate 70 70 69.7 82.5 Styrene 27.6 27.6 27.9 15.1 2-ethylhexyl acrylate 75    Methyl methacrylate 23.3  Acrylamide 1.9 1.8  1.9 1 1.9 2-hydroxyethyl 0.5 0.5 0.5 0.5 methacrylate Itaconic acid 0 0 1 0 Surfactants FES 993 (sodium 1.91 0.98 1.91 1.91 1.91 lauryl ether sulfate - 12 EO Units) Tergitol 15-S-40 0.49 0.48 0.49 0.49 0.49 (secondary alcohol ethoxylate - 40 EO units) Sodium 0 0.49 0 0 dodecylbenzene sulfonate Chase Package Sodium bisulfite 0.21 0   0.01 0.21 0.01 Isoascorbic acid 0 0.18 0.36 0 0.36 Properties.sup.1 Particle size (nm) 200-350 300-400 245-285 225-275 245-345 Tg (° C.) −8 −35    −13 −10 −30 pH 4.0-7.0 5.0-9.0 3.5-4.5 3.8-5   3.5-4.5 Viscosity (mPas) <1200 <800     200-700 200-600  200-1000 Solids (wt. %) 55-58 51-53 55-58 55-58 55-58 .sup.1For all properties with ranges given in the Comparative Examples, the ranges given are target values for the emulsion polymers which the inventors used; no measurements were taken for these polymers. For inventive Examples 1-3, the ranges cover the values actually obtained when more than one sample of the same polymers was used in repeated experiments; all test methods were as described above. The variations in the measured or target values within the ranges given are not critical to making the waterproofing membranes of the present invention.

[0060] To formulate the waterproofing membrane compositions or mortars, 100 weight parts aqueous emulsion copolymer indicated in Table 2, above solids and 100 weight parts fast curing dry mix powder composition solids were combined with 77 weight parts water (from wet aqueous emulsion copolymer plus additional water as needed), as described below.

[0061] To form the fast curing dry mix powder composition component, the cement, sand, polymer, and thickener were weighed and placed into a plastic (polyethylene) bag and then hand mixed for 2 minutes and conditioned at room temp (23° C.) for 24 hrs. After 24 hours, the aqueous emulsion copolymer component was prepared by adding the polymer and the indicated amount of water into a 2 I polyethylene beaker and stirring for 30 seconds at 200 rpm with a 4-wing stirrer (diameter: 75 mm). Then fast curing dry mix powder component was added within 45 s to the wet component. Stirrer speed was increased continuously from 200 via 700 up to 1100 rpm to have a good vortex in the mass. After combining all components, the paste was stirred for 135 s at 700 rpm to form a mortar.

[0062] After stirring was finished, if needed, a waterproofing membrane was formed from the mortar as set forth in the test methods below.

[0063] Test Methods

[0064] Particle Size: Particle size measurements were carried out using a dilute solution (<5% solids) of aqueous copolymer emulsion in either a Matec CHDF-3000 or Brookhaven BI90Plus Particle Size Analyzer and represent weight average particle sizes. The average of two measurements was used to determine the particle size.

[0065] Emulsion Viscosity: Viscosity was measured on the aqueous copolymer emulsions using a Brookfield Digital Viscometer with a stainless steel Brookfield RV-2 spindle at 60 rpm. The average of three measurements was used to determine the viscosity. All measurements were taken at room temperature.

[0066] Appearance: A waterproofing membrane was formed by planning the indicated mortar material with a smoothing trowel to cover the area bounded by two 200 mm×10 mm×2.2 mm thick metal slats fixed on opposite (widthwise) sides of a continuous polytetraflouroethylene film substrate (Bytac™ VF-81, SPI Supplies, West Chester, Pa.) resting on a 300×250 mm×10mm thick poly(vinyl chloride) plate support. Each membrane was dried, the two slats removed, and the membranes were carefully removed from the film substrate after 2 days. The membranes were inspected for the number and appearance of small cracks (<5mm long), large cracks (>5mm long), deep cracks and overall appearance. The film substrate was inspected for cracks that might get reproduced in the waterproofing membrane coated on the substrate so that there were no cracks in the substrate film that would influence the tensile test.

[0067] Elongation/Tensile Strength: (DIN ISO EN 527-1 and DIN ISO EN 527-2, March, 2010) 2.6 mm thick membranes of each indicated material were made as described in the Appearance test, above. The specimens cured under conditions of 7 days storage at 23° C./50% rel. humidity (RH), 7 days storage at 23° C. (RT)/50% RH followed by 7 days at 23° C. under water and 28 days at 23° C. (RT)/50% RH (7 days followed by 21 more days). After the 7 day RT cure, each of the cured membranes was then cut into fourteen (14 mm)/twenty one (21 mm) dumbbell shape specimens, as in DIN ISO EN 527-2 required type 1B (80 mm L×15 mm W with a narrow center section that is 10 mm W and 20 mm L). Seven (7) specimens of each cured membrane were tested immediately; seven (7) specimens of each cured membrane were cured 7 days under water at RT and then tested. Another seven (7) specimens were cured 21 more days at RT and 50% RH. To test, for each specimen thickness and width was measured at the thin part of the specimen 3 times for calculation of the sectional area before elongation. Elongation and tensile tests were run in a texture analyzer (TA.XT.plus Texture Analyser, Winopal Forschungsbedarf GmbH, Ahnsbeck, DE) at a speed of 20 mm/min and controlled via computer. Each specimen was fixed in the two clamps of texture analyser (60 mm distance between clamps). Measured was the distance between the clamps over time with the corresponding force needed to elongate the specimen elongated. The readings taken were maximum force; distance at maximum force and the distance at break (the distance at 50% max. force before break was taken, as this could be easy detected). From these readings, the percent elongation and maximum tensile strength, elongation at break and e-modulus or slope of the curve plotted as tensile strength vs. elongation were calculated. Reported values for each indicated material was the average of the seven (7) results calculated from readings for each specimen tested.

[0068] Acceptable tensile strength (28d) is ≧0.4 N/mm.sup.2 (MPa); Acceptable Elongation (28d) is ≧8%

[0069] Crack Bridging: According to EN 14891 (March, 2010). For each indicated mortar, concrete specimens (160×50×12 mm) were made from a mix of 28.9 wt. % CEM I 52.5R, 57.8 wt. % quartz sand F36, 0.3 wt. % superplasticiser (Glenium™ 51, BASF, Ludwigshafen, DE) and 13 wt. % water and cured 2 days at 23° C./50% rel. humidity and 26 days under water at 23° C. Once the concrete specimens were cured, each indicated freshly prepared mortar was applied to one concrete specimen using a metal frame of 3 mm thickness to one of the 160×50 mm sides of the specimen and allowed to dry for 4 h. Then, each freshly prepared mortar was applied to the other side of the specimen on which the same mortar had been applied using the same frame. Each specimen was cured 7 days at 23° C./50% rel. humidity. After curing, each cured specimen was broken carefully according to EN 14891(March, 2010) without destroying the membrane. The broken concrete specimen with the intact membrane was elongated with the texture analyzer at a speed of 0.15 mm/min, and the surface of the membrane was monitored visually. The reported distance was (1) at maximum force (2) when the first cracks appear. Additionally the maximum force was reported. An acceptable result is 0.4 mm, preferably less than 0.4 mm.

[0070] Pot-life: For determining the pot-life of a freshly prepared mortar, the viscosity at 23° C. of the mortar of the indicated composition was measured over time with a Brookfield viscometer (Model RVT DV-II, Brookfield Engineering Laboratories Inc., Middleboro, Mass., USA) in combination with a Brookfield Helipath stand (Brookfield Engineering Laboratories Inc., Middleboro, Mass., USA) on a Helipath at 23° C. and 50% rel. humidity, using a T spindle (up to 400 Pa.Math.s, usually changed to spindle T-E after 300 Pa.Math.s was reached) turned at 5 rpm. Each prepared membrane was filled into a 100 ml steel beaker. Air bubbles were avoided during the transfer. The steel beaker was jolted five times by hand and then the surface was smoothed with a scraper. The beaker with the mortar was placed beneath the Brookfield viscometer and the spindle was immersed into the centre of the mortar. The Brookfield viscometer was started and approx. 2 seconds after the display shows a stable figure, the Helipath stand was moved down to 11.5 mm within 30 seconds. The viscosity was measured 30 seconds after the beaker was filled (0 minutes=30 seconds), and the measurement was repeated after the indicated times. To prevent the sample from drying out or forming a skin, the steel beaker was covered by a plastic beaker during resting time between the measurements.

[0071] At each indicated time in Table 3, below, viscosity readings were taken after 5, 15, and 25 seconds. After 30 seconds the Helipath stand was switched to “upwards” and at 35, 45 and 55 seconds viscosity was read. For each time indicated in Table 3, below, the viscosity reported was the average of the 6 readings.

[0072] Pot life ends when the viscosity reaches a viscosity >1000 Pa.Math.s. An acceptable pot life is at least 120 min.

[0073] Density: Immediately after mixing, mortars were placed into a 100 ml steel beaker container of known volume and weight (inside diameter: 54 mm, height: (inside): 43.7 mm, wall thickness: 1.6 mm), tamped down, and then weighed. Density of the mortar is the weight divided by the volume of the mortar.

[0074] Time needed to apply second layer: The indicated freshly prepared mortar was applied at 1.3 mm thickness in one layer onto a lime stone brick. By a fingertip test every 5 min the freshness of the membrane was checked. When the membrane is set to the fingertip it is possible to apply a second layer and this time was recorded.

[0075] Water Impermeability: According to EN 12390-8 (March, 2010). A hole was drilled in a lime stone brick on the obverse side of the testing surface (nearly piercing ˜1 cm away from the testing surface). The indicated freshly made mortar was applied at 1.3 mm thickness in one layer on the lime stone brick. After 4 h a second layer of a freshly made mortar was applied at an added 1.3 mm on the first layer and allowed to dry for 7 days at 23° C. and 50% rel. humidity. A water indication paper (Wator 90610, Macherey-Nagel, Dueren, DE) was put into the drilled hole and then the membrane with the lime stone was put into the water impermeability tester (supplier: TESTING Bluhm & Feuerherdt GmbH, Berlin, DE) and a hydrostatic pressure of 1.5 bars was put on the membrane for 4 days. If the water absorption was less than 25 ml the pressure was raised up to 5 bars. If the absorption was higher the pressure was held additional 3 days at 1.5 bar. After the 7 days the water indication paper was checked. The test is passed if no humidity is seen underneath the membrane. In parallel the water loss over time was read from the calibrated cylinder of the water impermeability tester. In most cases, the membrane is water impermeable if water loss is below 40 ml after 7 days exposure.

[0076] Table 3, below, gives test results for each indicated mortar or membrane.

[0077] As shown in Table 3, below, inventive Examples 1 and 2 show that a second mortar layer can be applied in 50 min or less to the first applied layer, which is much faster than in the comparative Examples. However, the Comparative Example 1 mortar creates cracks as it cures, whereas the mortars of inventive Examples 1, 2 and 3 do not crack as they cure. Further, viscosity development of the fast setting mortars shows that the inventive mortar compositions have an acceptably long pot life. The membranes made from the mortars of inventive Examples 1, 2 and 3 show a dramatically increased elongation at max force and rupture, as well as maximum force. Finally, the membranes made from the mortars of Examples 1 and 2 exhibit dramatically improved crack bridging when compared to Comparative Examples 1 and 2, both in terms of deformation at maximum force and at rupture. The preferred compositions of the present invention have a glass transition temperature of −20° C. or higher. The inventive compositions this enable one to provide an excellent waterproofing membrane with good pot life, and a rapid cure.

TABLE-US-00003 TABLE 3 Results 1* 2* Example 1 Example 2 Example 3 Pot Life: Brookfield viscosity (Pas) (time after mixing>>)  0 min 54 13 59 108 56  5 min 98 16 62 108 61 15 min 182 23 68 142 67 30 min 569 31 127 221 110 45 min 1000 33 133 326 131 60 min 38 140 480-800 133 90 min 40 157 >1000 158 120 min  46 179 167 Density (g/cm.sup.3) 1.42 1.26 1.42 1.37 1.26 (immediate) Time needed to apply 35 80 50 30 75 second layer (min) Appearance Plenty of even even, nearly even, some Moderate rough; cracks, white nice lumps, white big nice & even spots also on spots on back surface; good front side side flexibility Elongation (water immersion, 7 d at RT and 50% RH/7 dH.sub.2O) tensile strength 0.45 0.34 0.51 0.62 0.21 (max force, N/mm.sup.2) average elongation 7.5 24.1 35.8 21.6 30.7 % at max. force average elongation 13.0 29.5 99.8 40.6 41.2 % at rupture average thickness 2.1 2.2 2.0 1.9 1.8 of layer (mm) Crackbridging (after 7 days at RT and 50% RH) max force (N) 149 68 123 164 68 deformation at 1.15 1.22 2.32 1.42 1.23 max force (mm) deformation at 3.33 2.33 7.11 4.06 2.67 rupture(mm) *Comparative Example.