BENTONE DS. Innovation Compliance High Performance. Application Leaflet February Key Benefits

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1 Application Leaflet February 2015 Rheology leadership plus so much more... Key Benefits Optimized workability by reduced stickiness BENTONE DS Superior sag and storage stability Partial replacement of cellulose ether Economical, highly efficient and refined Hectorite clay grade with excellent balanced performance for pasty, emulsion based renderings Innovation Compliance High Performance

2 Introduction Pasty, emulsion based renderings are typically used as finishing systems for wall applications. This modern product technology is combining performances, such as good water stability and weather resistance with the properties and durability of mineralic systems. Further, emulsion based renderings can be tinted using colourants to enhance the optical aspects of the treated object. To adjust and control viscosity, water retention and open time, cellulose ethers are typically being used. However, unwanted side effects of the cellulose ethers are the poor application properties and the strong tackiness on the tools. As these kind of renderings are typically being applied by hand, using a trowel, the lowest possible stickiness, resistance to flow and excellent workability are desired. The Hectorite based rheology modifier BENTONE DS has been designed to enhance the application properties of emulsion based renderings by reducing the resistance and stickiness on the tool. BEN- TONE DS strongly increases the low shear viscosity and flow point of the rendering. This typically results in improved sag control and stability. Additionally, a remarkable reduction of the cellulose ether content can be achieved by using BENTONE DS in the formulation. This does not adversly affect the open time. Moreover, the inclusion of BENTONE DS reduces the water sensitivity. In this leaflet, the outstanding performance of our Hectorite based BENTONE DS in comparison to unrefined Hectorite clays is displayed. Key Benefits Easier application due to reduced resistance and stickiness Excellent sag and slump control Optimum storage stability due to increased elasticity Less water sensitivity Partial replacement for cellulose ether No adverse affect on open time Chemical and Physical Data Composition Colour/Form Refined, beneficiated natural hectorite clay Milky-white, soft powder Solids content [%] 100 Density [g/cm 3 ] ca. 0.4 Particle size < 74 µm 93 Incorporation & Levels of Use BENTONE DS is easy to process and is typically recommended to be added under stirring to the water first. Than it should be mixed at the highest practicable speed for minimum 10 minutes to ensure sufficient hydration and delamination. Subsequently, all other ingredients can be added and incorporated to complete the formulation. Typical levels of additions for BENTONE DS are between 0.2% and 2.0% by weight on total formulation. However, depending on the degree of suspension or the desired rheological characteristics as well as which type of cellulose ether is being used, the ultimately required amount might differ. 2

3 Test System and Test Formulation Emulsion based rendering Compound Concentration [%] Water X Clay based additive X (0.3 or 0.15) Disperse for 10 minutes at 16 m/s Na-polyphosphate, 10% 0.3 NUOSPERSE FX DAPRO DF Biocide 0.2 Titanium dioxide 4.0 Disperse for 10 minutes at 6m/s The comparison study was performed in two parts. In the first part, the individual clay additives were added a fixed quantity of either 0.15% or 0.3%. In the second part of the study, the required amounts to achieve a flow table value of 16.5% were formulated. Formulations with 0.4% cellulose ether as a standalone thickener are mentioned as blank. In case of clay containing examples, the cellulose ether concentration has been reduced by 25% to a loading level of 0.3%. VAE based binder emulsion 13.2 Coalescing agent 1.3 Sodium hydroxide solution, w (NaOH) = Blend for 15 minutes in the Hobart-mixer Calcium carbonate fillers (various particle size) Practical examples Part 1: Clay based rheology modiers formulated at equal concentration Flow characteristics The rheograms below display the flow behaviour of rendering formulations with fixed clay concentrations. BENTONE DS provided significantly higher low-shear viscosities at both tested concentrations, 0.15% and 0.3%, than the natural, unrefined Hectorite, when formulated alternatively to 25% of the original cellulose ether content. The natural Hectorite grade causes only marginal changes to the blank with originally formulated 0.4% cellulose ether. 3

4 Flow point measurement The flow point was determined by extracting the shear stress necessary to exceed a damping factor/tan delta value of 1 from an amplitude sweep oscillation test. Exact test description can be found in the Appendix. The formulations with BENTONE DS displayed noticeably higher shear stress to exceed a tan delta value of 1 in comparison to the natural, unrefined Hectorite grade formulated at equal concentration. This value is defined as the flow point. However, as it might be difficult to read from the graph, the relevant values have been extracted and plotted in the following chart on the next page. 4

5 Sag control versus flow point Sag resistance (SR), defined as the maximum applicable layer thickness, was determined with a wedge blade application. The flow points (FP) were extracted from the above amplitude sweep curves. At a concentration of 0.15%, BENTONE DS provided a slightly higher sag stability and flow points than the blank with only cellulose ether. The use of the natural unrefined Hectorite clay grade resulted in only marginal performance differences compared to the blank at these concentration. At 0.3%, BENTONE DS clearly outperformed the unrefined, natural clay product on sag stability and flow point. Open time All rendering formulations containing a clay rheology modifier showed slightly longer open time compared to the blank formulation with pure cellulose ether. 5

6 Part 2: Flow performance at equal consistency adjusted to the relevant clay quantity Required concentration The concentration necessary to achieve a flow table value of 16.5 cm is displayed below. The use of BEN- TONE DS allows the use of noticeably lower loadings to obtain a flow table value of 16.5 cm when replacing 25% of the originally formulated cellulose ether portion. Flow characteristics The rheogram below displays the flow behaviour of rendering formulations at equal flow table values of 16.5 cm. The formulation with BENTONE DS showed significantly higher viscosities at low shear rates in comparison to the formulation containing the natural, unrefined Hectorite clay. 6

7 Flow point measurement The flow point was determined extracting the shear stress required to exceed a damping factor/tan delta value of 1 out of an amplitude sweep oscillation test. Exact test description can be found in the Appendix. Both formulations with either BENTONE DS or the unrefined, natural Hectorite clay provided comparable flow points when adjusted to equal consistency. Both formulations clearly outperformed the blank formulation with only cellulose ether. However, as it might be difficult to read from the graph, the relevant values have been extracted and plotted in the following chart. Sag control versus flow point Sag resistance (SR), noted as the maximum applicable layer thickness, was tested with a wedge blade application. The flow points (FP) were extracted from the amplitude sweep curves on the previous page. Both formulations with Hectorite clay performed similar with respect to the flow point. BENTONE DS provides slight advantages with respect to the maximum applicable layer thickness when adjusted to equal consistency. Both clay modified renderings clearly outperformed the blank formulation only containing cellulose ether. 7

8 Structure recovery The structure recovery test was determined by an oscillation test at fixed amplitude and frequency. Exact test description can be found in the Appendix. Both formulations displayed a very similar structure recovery after the removal of shear. Open time All rendering formulations containing clay demonstrated slightly longer open times compared to the blank formulation. 8

9 Ease of application/workability The use of clay in both cases resulted in significantly improved workability, less resistance and stickiness on the tool. The required loading level of BENTONE DS to achieve this effect is noticeably lower than with the unrefined, natural Hectorite grade. Water sensitivity The displayed water sensitivity is related to softening of the readily cured rendering on the relevant substrate when exposed to water. All tested cured plaster formulations performed equally good when exposed to water. 9

10 Conclusion When used at equal concentrations to replace 25% of the originally formulated cellulose ether quantity, the refined Hectorite grade BENTONE DS provides much stronger viscosity build, flow point and sag resistance than the unrefined, natural Hectorite grade. To adjust the renderings consistency to equal flow table values of about 16.5 cm, BENTONE DS requires much lower loadings than unrefined, natural Hectorite grade to replace 25% of the original cellulose ether portion. Using the individual quantities to equalize the consistency, the performance of the renderings with respect to low shear viscosity, sag control, flow point, workability and water sensitivity is comparable with both, BENTONE DS and the unrefined, natural Hectorite grade. In comparison to the blank, containing only cellulose ether, the use of either BENTONE DS or the natual Hectorite clay, results in significantyl improved low shear viscosity build, sag stability and workability. Appendix Test methods The flow table value was measured with the Haegermann flow table desk (DIN 18555, Part 2) when the table was dropped 15 times within 15 seconds. The lower the resulting value, the higher the viscosity. To test the sag resistance the renderings were applied with a wedge shaped blade (0-3 cm height) on gypsum plasterboards and stored vertically until cured. The maximum film thickness without sagging was recorded. The rheological characteristics (rheograms) were determined with the Anton-Paar MCR 300 rheometer, measuring geometry CC 27-P7 (bob and cup system, profiled) at a temperature of 23 C. Flow points were determined with a Anton-Paar MCR 300 rheometer, measuring geometry CC 27-P7 (bob and cup system, profiled), at a temperature of 23 C. The test was performed as an amplitude sweep. Therefore the shear stress was increased from 0.1Pa to 100 Pa at a fixed angular frequency of 10 s -1. The shear stress when the damping factor (tan delta) exceeded the factor of 1 was extracted and noted as the flow point. Structure recovery was measured using the Anton-Paar MCR 300 rheometer, measuring geometry CC 27-P7 (bob and cup system, profiled), at a temperature of 23 C. The test was performed in three individual ocillation parts: Step 1: 50 seconds at a strain of 0.1% and an angular frequency of 10 s -1. Step 2: 10 seconds at a strain of 10% and an angular frequency of 10 s -1. Step 3: 4 minutes at a strain of 0.1% and an angular frequency of 10 s -1. Workability or application properties were evaluated by applying the rendering with a smooth trowel on a vertical wall. The stickiness on the tool and the force required during the application were subjectively assessed. To evaluate the water sensitivity the renderings were applied on fibre concrete plates in a film thickness of 3 mm. After drying, the plates were stored for two hours in water. Soaking and rehardening were determined visually. To test the open time, the plaster was applied at a layer thickness of 3 mm on fibre cement plates. The period from the application until the the surface was not tacky anymore, was recorded as open time.. Learn more about our products and visit our website! or us at: waterinfo@elementis.com Elementis UK Ltd c/o Elementis GmbH Stolberger Strasse Cologne, Germany Tel: Fax: Elementis Specialties, Inc. 469 Old Trenton Road East Windsor, NJ USA Tel: Fax: Elementis Specialties Asia No. 99 Lian Yang Road Songjiang Industrial Zone Shanghai P.R. China Tel: