CW40-707 Waterproof VAE Emulsion

In the production of two-component polymer-modified cementitious waterproof coatings intended for continuous immersion service in swimming pools and wetroom sub-floors, the interaction between CW40-707 and the hydrating cement matrix dictates failure mode. The liquid component is pre-compounded in a closed-loop rotor-stator mixer operating at 400–600 rpm for 20 minutes, combining CW40-707 (supplied at 55% ± 1% solids, Tg approximately −18 °C) with a polysiloxane defoamer and a polycarboxylate superplasticiser. The powder component, manufactured via a twin-shaft compulsory mixer with a mixing time of 180 seconds, consists of CEM I 42.5 R Portland cement, graded silica sand (0–0.5 mm), and a cellulose ether providing slump retention. At the jobsite, the liquid and powder are combined in a 1:2.5 weight ratio using a slow-speed spiral paddle mixer (<300 rpm) to limit air entrapment above 2%. The polymer-to-cement ratio (P/C) on a solids basis sits optimally between 0.18 and 0.25; at P/C 0.25 the cured membrane exhibits crack-bridging capacity exceeding 0.75 mm at −10 °C per testing conforming to EN 14891:2017 clause 5.4.3. When the P/C ratio is pushed beyond 0.30, a documented mechanical inversion occurs: compressive strength collapses from 28 MPa to below 12 MPa after 28 days of wet curing, while elongation at break surpasses 160%, creating a film that fails by cohesive tearing under hydrostatic pressure. The finished product is a two-pack flexible cementitious waterproof slurry—typically a liquid in a 20 L pail and a 25 kg powder bag—applied by notched trowel or airless spray at a wet-film thickness of 1.2–1.5 mm. Post-application, a 48-hour fog-cure at >90% RH is mandatory before ponding tests; early hydration interruption leads to surface crazing visible under magnification at 10×. This configuration meets the full suite of EN 14891:2017 requirements for liquid-applied water-impermeable products beneath ceramic tiling and aligns with the Chinese compulsory GB/T 23445-2009 Type II performance thresholds.

At What Polymer Content Does Tensile Adhesion Inversion Occur in Thin-Layer Waterproof Mortars Subjected to Carbonation Cycling?

The substitution of standard mixing water with CW40-707 emulsions in dry-mix waterproofing mortars shifts the post-carbonation adhesion profile in a non-linear fashion. Mortars formulated with a polymer solids-to-cement ratio of 0.12–0.15 are processed in a horizontal single-shaft ploughshare mixer where pre-blended powders (CEM II A-L 42.5 N, 0.1–0.6 mm quartz aggregate, and a polyvinyl alcohol-based anti-cracking fiber at 0.5 kg/m³) are sprayed with a CW40-707 dilution (pre-diluted to 30% solids with deionised water) over a 90-second wetting cycle to achieve a final moisture content of 13–15%. The damp mortar is extruded through a PFT G5 continuous mixer and spray-applied in 2–3 mm lifts onto concrete substrates pre-conditioned to a moisture level below 4% as measured by a Tramex CMEX II meter. Cured under 5% CO₂ atmosphere for 28 days to simulate urban carbonation, the formulation’s pull-off strength was evaluated following EN 1542:1999 and EN 1504-2 substrate bonding protocols. When the polymer solids exceed 0.18 of cement mass, tensile adhesion strength drops from an initial 2.1 MPa to 0.9 MPa—a severe adhesion cliff attributed to excessive polymer film coalescence at the interface that obstructs capillary pore ingress of newly formed calcium silicate hydrate. Batch-to-batch variance in the residue moisture of the powder premix, when exceeding ±0.3%, introduces a measurable adhesion scatter of ±0.25 MPa. The permissible saw-cut time window narrows to only 5–8 hours after spraying; delayed cutting fractures the partially coalesced polymer network. The terminal product is classified under EN 1504-2 as a surface protection coating for concrete (MC) and is supplied as a pre-packaged silo mortar for mechanised application, with CW40-707 provided in 1,000 L IBC totes for direct coupling to the mixing pump. Compliance with the anti-carbonation requirement of EN 13295 demands that the diffusion-equivalent air layer thickness S_d remains above 50 m after 2,000 hours of UV ageing per ISO 16474-2 cycle A.

Liquid-Applied Damp-Proof Membrane Formulation for Wetroom Installations and the Zero-Slump Mandate

Formulators targeting a trowel-grade, single-component liquid membrane suitable for vertical wetroom walls without shutter support must reconcile the film’s low-shear viscosity with its sag resistance. CW40-707, constituting 42–48% of the total wet formulation weight, is compounded in a vacuum-rated planetary disperser (vacuum level −0.08 MPa) with 100 μm aluminium silicate extender, a hydrophobic fumed silica thixotrope at 1.5–2.0%, and an associative polyurethane thickener to deliver a complex viscosity of approximately 300 Pa·s at 0.1 rad/s. Deaeration under vacuum continues until the wet density stabilises at 1.18 ± 0.02 g/cm³, a critical step because residual microbubbles nucleate blowholes during subsequent top-coat tiling. Application by a 4×4 mm notched squeegee yields a dried film thickness of 0.6–0.8 mm per coat, with the second coat applied wet-on-dry after an interval of 45–60 minutes at 23 °C/50% RH. The membrane’s water vapour transmission rate, measured under ASTM E96 Procedure B (wet cup), registers 1.5–2.3 g/m²·h, satisfying the breathability criterion without compromising the 24-hour watertightness test of EN 14891:2017 § 5.4.1. Once the film is fully coalesced—typically after 7 days at 23 °C—tensile adhesion to concrete exceeds 1.2 MPa when tested per ASTM D7234-12. Transport of the product as a paste in 15 L pails imposes a freeze-thaw constraint: if the shipment experiences more than 3 cycles between −5 °C and +25 °C, the low-shear viscosity increases irreversibly by 40–55% due to pre-coalescence, rendering the membrane unworkable. The product is a ready-to-use damp-proof membrane for internal wet areas, and its formulation aligns with the emission limits for volatile organic compounds set out in AgBB 2021 and the French CLP classification A+.

When Continuous Filament Mat Reinforcement Is Eliminated from a Cement-Free VAE Roof Coating Applied Over Polyisocyanurate Insulation

Over low-density polyisocyanurate (PIR) panels with a surface friability exceeding 0.8 g/h (DIN abrasion wheel test), the direct application of an unreinforced CW40-707-based elastomeric coating requires a precise crosslink adjustment. The coating’s binder content reaches 38–42 wt% of the batch, extended with 15 μm precipitated calcium carbonate and a non-migratory polymeric plasticiser to maintain an elongation at break above 400% at −15 °C (ISO 37:2017 type 2 dumbbell). Processing entails premixing CW40-707 with an aziridine crosslinker (0.3–0.5 phr) in a low-shear anchor agitator for 10 minutes, then dispersing the slurry in a high-speed dissolver at a tip speed of 22 m/s until a grind gauge reading of <40 μm is attained. A spray train consisting of a Graco Merkur 30:1 pump and a reversible flat tip deposits a monolithic coat of 1.0 mm dry film thickness in a single pass. Cure proceeds by evaporation of moisture and simultaneous aziridine ring-opening; the coating must be protected from rainfall for a minimum of 6 hours post-spray. The absence of a reinforcing fleece makes the film vulnerable to wind-driven dynamic punctures, and thus the standard ASTM D5602-19 static puncture test is replaced by a dynamic drop probe test per EN 12691:2018 where the coating must sustain a 500 mm drop without visible cracking. The final product is a cold-fluid-applied waterproofing system for inverted roof assemblies—compliant with ETAG 005 and EN 1504-2 coating class C—packed in 200 L drums for spray contractors. In accelerated aging under ISO 12944-9 cyclic conditions, gloss retention measurements with a 60° geometry glossmeter drop to 20% after 1,000 hours, which is acceptable for a buried or ballasted roof configuration but insufficient for exposed aesthetic roofs.

Hydrostatic backpressure against a tunnel lining substrate—regularly exceeding 0.3 MPa during seasonal groundwater fluctuations—requires an interfacial adhesion profile that remains above 1.5 MPa after 2,000-hour water immersion at 40 °C. In split-batch spraying operations, a high-build mortar is prepared by mixing CW40-707 pre-diluted to 25% solids with a mechanically pre-blended dry mix of CEM I 52.5 N—silica fume ratio of 8:1, accelerator, and polyacrylonitrile microfibers at 0.9 kg/m³. The polymer solids are held at 5–8% of total binder weight, because higher dosages retard early strength gain to below the critical 1 MPa at 12 hours necessary for safe geotextile attachment. A wet-mix shotcrete rig equipped with a Schwing S 20 E concrete pump delivers the material at 12–14 m³/h, with the accelerator added at the nozzle through a separate metering line. The composite lining—a 50 mm layer reinforced by a non-woven drainage geotextile—is cured under a polyethylene sheet for 72 hours to prevent rapid moisture loss that causes gradient polymer skinning. Adhesion pull-off tests executed in accordance with EN 1542 at 7, 28, and 90 days map a progressive increase from 1.2 MPa to a plateau of 2.3 MPa, but only if the soluble calcium ion concentration in the mixing water is maintained below 150 mg/L; hard water (> 300 mg/L CaCO₃ equivalent) destabilises the VAE dispersion and generates microgels that reduce tensile bond strength by 30%. The cured composite’s chloride ion permeability, measured under ASTM C1202-22, consistently falls below 500 Coulombs, qualifying it as a very low permeability barrier according to AASHTO criteria. The end product is a sprayed waterproofing membrane defined within the scope of EN 1504-2 principle PI (protection against ingress) and is delivered as a twin-stream kit: CW40-707 in 1,000 L returnable totes and the dry mix blend in 1,500 kg big bags or bulk silo.