ELOTEX FX2311

Slump retention is not the only variable in anhydrite-based self-leveling compounds

When FX2311 is compounded into a ternary binder system based on ordinary Portland cement, calcium aluminate cement, and anhydrite, the dry-mix addition is typically between 1.5 wt% and 4.0 wt% of total dry powder. The powder is a vinyl acetate–ethylene copolymer with a reported glass transition temperature of approximately −7 °C and a minimum film forming temperature near 0 °C. Bulk density falls between 450 g/L and 650 g/L; residual ash after 1000 °C is approximately 10–14%; the redispersed slurry pH is typically 6.5–8.5. These values place the material in the low-Tg VAE class suitable for floor levelling compounds without external coalescents. The dry-mix is produced in a compulsory twin-shaft mixer or continuous ribbon blender before water is added; wet mixing above 600 rpm can destabilise the redispersed polymer particles and entrain air. Water demand is normally balanced between 0.20 and 0.24 L/kg of dry mortar, depending on filler surface area and superplasticiser type. Flow spread is evaluated under EN 12706, and the hardened screed is classified under EN 13813:2002; target classes are commonly CT-C25-F6 to CT-C30-F7. The polymer modifies plastic viscosity and reduces bleeding without acting as a set retarder. Overdosing citric acid or tartaric acid above 0.3 wt% can delay strength gain and suppress film coalescence below 10 °C, which results in a dusty surface after 24 h. Powder storage above 60% relative humidity may require pre-drying to avoid lumps and flow variability in continuous mixing plants. Applied thicknesses from 3 mm to 20 mm are pumped or trowelled onto prepared concrete, anhydrite, or steel substrates. The cured layer receives vinyl, engineered wood, LVT, or ceramic tile once residual moisture is below the adhesive manufacturer’s limit.

Does open time in C2TE tile adhesive degrade after high-shear mixing?

Open time in a cementitious tile adhesive is not controlled solely by cellulose ether dosage. In a C2TE formulation, FX2311 is compounded at 2.0 wt% to 4.0 wt% with CEM I 42.5 R, silica sand 0.1–0.3 mm, a hydroxyethyl methyl cellulose blend, a starch ether, and an alkali-resistant defoamer. The mixed adhesive is adjusted to a water-to-powder ratio of 0.22 to 0.26, and viscosity is controlled by the cellulose ether rather than by the polymer. Classification is verified under EN 12004:2007+A1:2012 and ISO 13007-1:2014. Tensile adhesion strength is determined by EN 1348:2007; transverse deformation is determined by EN 12002:2015. For a C2TE S1 adhesive, adhesion must remain at least 1.0 N/mm² after water immersion, heat ageing, and freeze–thaw cycling. For an S2 product, transverse deformation must reach at least 5 mm. High-shear mixing above 800 rpm can increase slurry temperature and reduce open time; the typical field symptom is skinning across the trowel notch before tile embedment. FX2311 contributes low-Tg film formation that holds aggregate at the interface after water loss but does not function as a casein-based tackifier. Open time is checked at 20 min and 30 min; published comparative data for this specific powder at 3 wt% is limited, so open time must be confirmed with the selected cellulose ether blend and substrate absorbency. End uses include large-format porcelain tiles, low-absorption ceramic tiles, and installation over residual old adhesive or gypsum surfaces where a suitable primer is applied.

Repair mortar R2/R3 compressive envelopes and polymer film formation

In a polymer-modified repair mortar, FX2311 is added at 2.0 wt% to 5.0 wt% to improve adhesion to prepared concrete and to reduce restrained shrinkage cracking. The relevant product standard is EN 1504-3:2005; for R2 and R3 class materials, compressive strength is tested by EN 12190, pull-off adhesion by EN 1542, and chloride ion content by EN 1015-17. Thermal compatibility testing referenced by EN 13687-1 is relevant for R3 and R4 systems and can expose interfaces where polymer film continuity is incomplete. For context, R2 requires compressive strength of at least 15 N/mm², R3 at least 25 N/mm², and R4 at least 45 N/mm²; chloride ion content must not exceed 0.05% by mass in all classes. FX2311 cannot by itself upgrade an R2 formulation to R4; that conversion requires a sufficiently high cement content, a low water-to-binder ratio, and usually silica fume or metakaolin. The polymer film begins to coalesce when the substrate and mixed mortar temperature exceed 10 °C. Below that threshold, adhesion development is delayed and the repair may require heated substrates or insulated blankets. Mixing should be carried out in a forced-action mixer at water-to-dry ratios between 0.14 and 0.18, depending on aggregate fines and cement strength class. The substrate must be saturated surface-dry before application; a dry substrate absorbs water from the interfacial zone and reduces film continuity. Application thickness ranges from 5 mm for surface patches to 40 mm for vertical sections. End products include concrete balcony repairs, spalled column edges, and soffit patches where lightweight aggregate reduces the load on formwork.

When gypsum joint compounds require low-Tg film coalescence without retarding set

Gypsum-based finishing compounds benefit from FX2311 only when the addition is balanced with accelerators or retarders. The dosage in a joint compound is usually 1.0 wt% to 3.0 wt% of the dry mix. The low-Tg vinyl acetate–ethylene copolymer increases flexibility and reduces edge-sand-through at tapered board joints. The product standard is EN 13963:2014 for gypsum jointing compounds; in North America, ASTM C474 applies to joint compound testing. Film formation occurs at room temperature; no coalescing solvent is required because the minimum film forming temperature is near 0 °C. The polymer does not provide biocide function; preserved mixing water or dry-film preservatives are required for prolonged wet storage. Overdosing FX2311 above 3 wt% can reduce sandability and increase paint holdout variation on the finished seam. Mixing is carried out with a low-speed drill mixer below 500 rpm to avoid air entrainment that produces pinholing. End products include joint finishing compounds, skim coats, and gypsum underlayments for interior walls and ceilings.

Polymer-modified cementitious slurries applied as two-coat tanking systems often fail crack-bridge tests because film coalescence is incomplete at low substrate temperature, not because the cement matrix is weak. FX2311 is compounded at 3.0 wt% to 6.0 wt% into a mix of CEM I 42.5 R, silica sand 0.1–0.5 mm, a water-reducing and coalescing package, and a powdered defoamer. The slurry is applied by brush, trowel, or spray over concrete, masonry, or tile backer board. The first coat is applied at 0.8 mm to 1.2 mm wet; a reinforcing glass-fibre mesh is embedded before the coat skins. The second coat follows after 24 h to produce a total dry film thickness of 1.5 mm to 2.5 mm. The relevant standard is EN 14891:2017 for liquid-applied water impermeable products beneath ceramic tiling. Crack-bridging performance is assessed under a defined crack-opening displacement, commonly 1 mm at low temperature depending on the application class. Water impermeability is tested under a hydrostatic pressure of 1.5 bar for 7 days. FX2311 contributes film flexibility and adhesion to damp substrates, but the formulation must include a defoamer because high-air-entraining cellulose ethers and VAE redispersions can otherwise leave capillary pathways. The cured slurry is not a structural waterproofing layer; it must be protected from UV exposure and installed beneath tile, stone, or a cementitious screed.

Adhesion failure of expanded polystyrene boards in an ETICS base coat is commonly traced to low polymer film continuity at the glass-fibre mesh line, where the embedment mortar is thinnest, rather than to the insulation board itself. In an adhesive and base coat mortar, FX2311 is dry-compounded at 2.5 wt% to 5.0 wt% with CEM I or CEM II, limestone filler, silica sand 0.1–0.5 mm, a cellulose ether, and a powdered air-entraining agent where required. The system is assessed under ETAG 004 or the current European Assessment Document EAD 040083-00-0404. Adhesion to EPS and mineral wool is measured by EN 13499 or the method referenced in the ETICS EAD. A typical acceptance criterion is 0.08 N/mm² minimum tensile adhesion to EPS after conditioning. The base coat is applied as a 4 mm to 6 mm layer, the reinforcement mesh is embedded, and a second pass is applied before the first layer skins. At substrate temperatures below 5 °C, FX2311 film formation is retarded; this condition can produce a weak interface between the mesh and the insulation board. The polymer helps maintain workability and reduces surface crusting, but it does not replace a hydrophobic additive for water absorption control. The end products are adhesives for EPS and mineral wool boards and reinforcing base coats for exterior insulation systems.