CELVOLIT 1309 VAE Emulsão para lodos impermeabilizantes cimentosos

In two-component cementitious waterproofing slurry systems, the liquid polymer component functions as both a water-replacement vehicle and a film-forming binder that welds hydrate phases into a cohesive, flexible membrane. CELVOLIT 1309 is an aqueous dispersion of a vinyl acetate-ethylene (VAE) copolymer, stabilized with a protective colloid system selected for controlled interaction with Portland cement and calcium aluminate cements. At a polymer-to-powder ratio of 0.30:1 to 0.40:1 by weight, the dispersion replaces gauging water while maintaining a workable consistency that permits trowel or brush application at thicknesses from 0.8 mm to 2.5 mm wet. The copolymer’s built-in ethylene sequences depress the glass transition without external coalescents, yielding a minimum film-forming temperature (MFFT) near 0 °C and enabling membrane formation under damp-substrate conditions that would defeat plasticized homopolymer dispersions.

What distinguishes VAE emulsions from styrene-butadiene latex in cementitious membrane formulations?

Styrene-butadiene (SB) latex, widely used in waterproofing, relies on copolymerized styrene for stiffness and butadiene for low-temperature flexibility. In alkaline cement pore solutions, the unsaturated backbone of SB is susceptible to oxidative degradation over prolonged water immersion, and residual emulsifiers can contribute to post-cure water spotting. VAE copolymers, by contrast, possess a fully saturated carbon backbone that is inert to the hydroxide and sulfate environments present in hydrated cement; the ethylene comonomer imparts permanent flexibility without the oxidative lability of pendant double bonds. When CELVOLIT 1309 is incorporated at ≥15 parts per hundred dry cementitious powder, the resulting membrane exhibits a wet adhesion pull-off strength that typically exceeds 1.0 MPa on moist concrete, measured per EN 1542:1999, because the vinyl acetate units generate secondary bonding to calcium-silicate-hydrate surfaces through acetate coordination. This intrinsic adhesion reduces the dependence on substrate primers and eliminates the need for solvent-borne tackifiers common in SB-modified formulations.

Delivery Form and Physicochemical Profile

As supplied, CELVOLIT 1309 is a milky-white liquid with a faint vinous odor, classified as non-hazardous under Regulation (EC) No 1272/2008. The product is preserved with a formaldehyde-free biocide package and is manufactured without alkylphenol ethoxylates (APEO), fulfilling REACH Annex XVII restrictions on nonylphenol derivatives. The particle size distribution, centered near 1.5 µm, confers high shear stability during mechanical mixing yet remains coarse enough to minimize air entrainment when combined with the powder component.

Prior to blending the liquid polymer with the dry powder component, the cementitious premix must be thoroughly dry-blended to disperse high-range water-reducing agents, defoamers, and setting modifiers. The dispersion is added under low-shear agitation with a variable-speed drill (typical spindle speed 400 – 600 rpm) equipped with a helical ribbon mixer; high-shear dispersion tools such as Cowles blades are avoided because localized turbulence can nucleate agglomerates and prematurely entrain air. The initial endothermic wetting phase should be sustained for 120 s before a resting period of 60 s to allow de-aeration, followed by a final 60 s of mixing. The pot life of the resulting slurry, defined as the interval until the Brookfield viscosity doubles, lies in the range of 45 – 75 min at 23 °C and 50 % RH. Beyond this window, workability collapses gradually, and pigment settling becomes visible; re-tempering with additional polymer dispersion is not permissible because it distorts the polymer-to-cement ratio and creates hydration-inhomogeneity planes that reduce tensile adhesion by up to 40 % in pull-off tests per ASTM D4541-17.

When CELVOLIT 1309 replaces standard acrylic dispersions in heavy-duty waterproofing

Pure acrylic emulsions, although widely employed for their UV resistance and early water resistance, often impart a pronounced thermoplastic character to cementitious membranes. Under permanent hydrostatic loading at 1.5 bar, membranes modified with conventional styrene-acrylic or pure acrylic dispersions may exhibit creep and thickness-dependent water absorption, especially when the polymer dosage exceeds 20 % by mass of the dry mix. CELVOLIT 1309 forms a semi-interpenetrating network within the cement hydrate matrix that restricts long-range polymer chain mobility while retaining low-strain flexibility. This morphological restraint translates into lower equilibrium water uptake and higher resistance to blistering during sustained water immersion. Comparative data, measured on 2 mm dry film thickness specimens cured for 28 days at 23 °C and 95 % RH, is presented below.

Performance Metrics at 2.0 mm Dry Film Thickness

When tested according to the liquid-applied waterproofing kit standard EN 14891:2013 (CM type, kit class O), a CELVOLIT 1309-modified slurry applied at 1.8 – 2.2 kg/m² and cured for 7 days under fog-room conditions passes the hydrostatic pressure resistance test (250 kPa for 24 h with no penetration) and exhibits initial crack bridging of 1.0 mm at −5 °C without failure. Tensile adhesion after water contact measured on concrete slabs at (23 ± 2) °C consistently exceeds 0.8 MPa, with cohesive failure within the substrate rather than at the polymer–cement interface. Published data for this specific emulsion grade under fully submerged, brine-exposed conditions is limited; however, cyclic immersion-drying tests on reinforced concrete blocks indicate that the VAE membrane retains ≥85 % of its initial peel strength after 50 cycles of alternating salt fog (5 % NaCl, 35 °C) and oven drying at 40 °C.

The polymer is not designed for use in continuous acid-exposure environments (pH < 4.0) or in contact with ester-based plasticizers that may migrate from adjacent PVC layers; such exposure causes accelerated ester hydrolysis at the vinyl acetate units and gradual embrittlement. Substrate temperatures below 5 °C during application delay film coalescence and increase the risk of partial film fracture when the membrane is submerged prior to full cure. The liquid dispersion must be protected from freezing; storage below 0 °C can induce irreversible particle flocculation and viscosity drift beyond 3000 mPa·s, rendering the material unsuitable for uniform powder wet-out. Concurrent use with high-alumina cement blends that generate rapid early ettringite formation may result in unacceptably short open times (< 20 min); formulation adjustments with delayed-release set retarders are required in such cases. No compatibilization with amine-based accelerators is recommended, as the alkaline amine environment can degrade the protective colloid and cause localized gelation.