| HS Code | 192035 |
| Appearance | White free-flowing powder |
| Polymer Base | Vinyl Acetate-Ethylene (VAE) copolymer |
| Solids Content | 99% minimum |
| Bulk Density | 400-600 g/L |
| Particle Size | 10% maximum retained on 300 mesh |
| Minimum Film Forming Temperature | 0-5 °C |
| Glass Transition Temperature | -10 to 0 °C |
| Elongation At Break | 300% minimum |
| Tensile Adhesion Strength | 1.0 MPa minimum |
| Water Resistance | Excellent, with low water absorption and high wet adhesion |
As an accredited Flexible RDP for Waterproofing Mortars factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Supplied in 25 kg moisture-proof laminated paper bags with inner polyethylene liner for safe storage and handling. |
| Container Loading (20′ FCL) | 20' FCL container loading: Flexible RDP for waterproofing mortars, packed in 25kg bags, palletized and shrink-wrapped for safe transport. |
| Shipping | Flexible RDP (redispersible polymer powder) for waterproofing mortars is shipped in moisture-proof laminated bags, typically 20–25 kg, on pallets. Store in cool, dry conditions, protected from humidity and direct sunlight. Avoid excessive pressure during transport to prevent bag damage, ensuring product stability until use. |
| Storage | Store flexible RDP in a dry, cool, well-ventilated area, away from moisture, rain, and direct sunlight. Keep tightly sealed in original packaging to prevent caking and contamination. Avoid high temperatures, stacking pressure, and damage to bags. When stored properly under these conditions, the powder retains its performance for up to 12 months. |
| Shelf Life | Flexible RDP for Waterproofing Mortars has a shelf life of 12 months when stored unopened in a cool, dry place. |
A one-component cementitious slurry for balcony and wet-room tanking is dry-blended with 3.0 wt% to 5.0 wt% of a flexible VAE or acrylic RDP having a glass transition temperature between -15 °C and -5 °C and a minimum film-forming temperature not above 2 °C. The RDP is pre-blended with 0.2 wt% to 0.5 wt% of cellulose ether and 0.05 wt% to 0.10 wt% of a powdered air-entraining agent before the sand and cement fractions are added. The dry mix is processed in a twin-shaft compulsory mixer with rotor speed held below 90 min⁻¹ because frictional heating above 50 °C causes the RDP particles to tackify and form lumps on the ploughshare blades. Water demand is typically 20 wt% to 24 wt% of dry mix; increasing RDP content from 3.0 wt% to 5.0 wt% raises the water demand by 1.5 wt% to 2.5 wt% and shifts the rheology from a brushable slurry to a trowel-grade paste. The mixed material is applied in two or three passes to a total wet-film thickness of 1.5 mm to 2.0 mm. After hydration begins, the membrane must be cured at 20 °C and above 85% relative humidity for at least 48 h; if ambient relative humidity falls below 60%, coalescence of the redispersed polymer particles remains incomplete and surface dusting develops. The cured membrane is tested for water impermeability and crack bridging under EN 14891:2017. For O2-class crack bridging at 1.5 mm, the polymer-cement ratio is maintained between 0.06 and 0.10. The terminal use is a tiled balcony, bathroom floor, or shower enclosure where the membrane blocks chloride-bearing water from reaching the structural slab.
For underwater tile adhesive formulations required to meet C2S1 classification under ISO 13007-3 and EN 12004:2017, flexible RDP is charged at 2.5 wt% to 4.0 wt% of dry mortar. The powder is dry-blended with 30 wt% to 40 wt% of white CEM I 52.5 R, 55 wt% to 65 wt% of graded quartz sand, 0.3 wt% to 0.6 wt% of cellulose ether, 0.1 wt% to 0.3 wt% of starch ether, and 0.5 wt% to 1.0 wt% of calcium formate accelerator. The twin-shaft compulsory mixer is run in short cycles at 75 min⁻¹ to 95 min⁻¹; overmixing beyond 3 min can generate electrostatic charge and cause fine RDP particles to segregate. The hardened adhesive must show transverse deformation of at least 2.5 mm for S1 and 5.0 mm for S2, while tensile adhesion after water immersion is specified in ISO 13007-1. Flexible RDP reduces water absorption of the adhesive bed but raises the risk of shear creep under heavy porcelain tiles when dosage exceeds 4.5 wt%. The production-scale failure mode observed in this segment is not adhesive debonding but tile slip: excessive low-Tg polymer delays cement setting and extends open time beyond the point where a mosaic sheet can be adjusted. The terminal application is the fixing of glass mosaic and porcelain tile in continuously submerged pool basins, where the adhesive layer remains saturated for the service life.
EN 1504-3 class R3 repair mortar for non-structural wet concrete repair requires a 28-day compressive strength of at least 25 MPa. Flexible RDP is introduced at 2.0 wt% to 4.0 wt% to reduce capillary water absorption, improve adhesion to the prepared concrete substrate, and accommodate micro-movement at the interface. The polymer-cement ratio is controlled at 0.05 to 0.08 because higher RDP dosage depresses compressive strength and can drop the mortar below the R3 threshold when the cure temperature exceeds 35 °C. The dry mix also contains 5.0 wt% to 10.0 wt% silica fume and 0.5 wt% to 1.0 wt% of a powdered shrinkage-reducing admixture. Mixing is performed in a forced-action paddle mixer with a 4-minute wet cycle at 40 min⁻¹ to 60 min⁻¹; longer wet mixing breaks the polymer film after coalescence begins and entrains air. The substrate is prepared to saturated surface-dry condition, with free water removed by compressed air. Application is by trowel in layers of 5 mm to 30 mm. Curing under damp hessian is maintained for 5 d, followed by 2 d air drying before water contact. The terminal products include repair of sump bases, concrete tank floors, spillway aprons, and wet sewage channels where continuous water exposure is expected but acid concentration is low. Continuous contact with sulphuric acid below pH 3 attacks the cement matrix regardless of RDP; published data for acid-resistant RDP repair mortar under EN 1504-3 remains limited.
| Segment | Typical dosage | Polymer-cement ratio | Governing standard | Critical threshold |
|---|---|---|---|---|
| One-component tanking slurry | 3.0 wt% to 5.0 wt% | 0.06 to 0.10 | EN 14891:2017 | Crack bridging 1.5 mm O2 |
| Submerged tile adhesive | 2.5 wt% to 4.0 wt% | 0.05 to 0.08 | ISO 13007-3 | Transverse deformation 2.5 mm S1 |
| Wet concrete repair mortar | 2.0 wt% to 4.0 wt% | 0.05 to 0.08 | EN 1504-3 | Compressive strength 25 MPa R3 |
| Negative-side basement slurry | 4.0 wt% to 6.0 wt% | 0.10 to 0.14 | ASTM D7088-17 | Hydrostatic head 2 bar |
In below-grade negative-side installation on concrete block and cast-in-place concrete walls, the water pressure acts to push the waterproofing layer away from the substrate, so adhesion and microcrack-bridging capacity govern the formulation. Flexible RDP is charged at 4.0 wt% to 6.0 wt% of the dry mix, with polymer-cement ratio between 0.10 and 0.14. The blend contains 35 wt% to 45 wt% CEM I 42.5 R, 40 wt% to 55 wt% fine silica sand of 0.1 mm to 0.5 mm, 5.0 wt% to 10.0 wt% metakaolin or silica fume, 0.3 wt% to 0.6 wt% cellulose ether, and 0.1 wt% to 0.3 wt% of short polypropylene fibres to control plastic shrinkage. The slurry is mixed to a viscosity of 1,500 mPa·s to 2,500 mPa·s and applied with a medium-bristle brush or steel trowel in two to three coats to a dry film of 2.0 mm to 3.0 mm. Each coat is allowed to set for 4 h to 8 h before the next pass. Hydrostatic pressure resistance is evaluated under ASTM D7088-17; adhesion after water ageing is tested under EN 14891:2017 with a minimum tensile adhesion of 0.5 MPa for the relevant class. The field failure mode is moisture-driven blistering when the substrate remains wet during application; the operational boundary is a substrate surface humidity below 75% and no free water film. The terminal installations are basement interior walls, lift pits, underground parking retaining walls, and utility vaults where exterior excavation is not feasible.
An ETICS base coat over EPS insulation functions as a thin weather-resistive cementitious layer that must maintain adhesion to the insulation board and control capillary water ingress into the system. Flexible RDP based on ethylene-vinyl acetate is added at 2.0 wt% to 3.5 wt% of the base coat dry mix; this dosage is lower than in tanking slurries because the base coat must remain hard enough to support the embedded glass-fibre mesh under impact loading. The base coat composition includes 25 wt% to 35 wt% CEM I 52.5 R, 40 wt% to 55 wt% limestone or quartz sand, 10 wt% to 20 wt% hydrated lime, 0.2 wt% to 0.4 wt% cellulose ether, and 0.1 wt% to 0.3 wt% of a rheology-modifying starch ether. The dry mix is processed in a horizontal ploughshare mixer at 60 min⁻¹ to 80 min⁻¹; mixing time is extended by 30 s after RDP addition to achieve uniform powder distribution without overheating. The wet mortar is applied at 4 mm to 6 mm thickness with the mesh embedded in the upper third. Capillary water uptake of the cured base coat must remain below the limit defined in ETAG 004 for the factory-assembled kit; water absorption through the base coat is further reduced by the hydrophobic film formed from the RDP after drying. The operational boundary is that high RDP dosage above 4.0 wt% makes the base coat too elastic and reduces its impact resistance under ETAG 004 hard-body impact testing. The terminal use is a facade weather barrier on EPS or mineral-wool insulation, where the base coat prevents rain penetration and supports the finishing render.
Grout joints in continuously immersed ceramic-lined tanks and swimming pools require a cementitious grout with low water absorption and sufficient flexion to survive thermal cycles from pool water temperature changes. Flexible RDP is charged at 1.5 wt% to 3.0 wt% of dry grout, because the high cement-to-sand ratio already produces high density and the RDP is present mainly to reduce microcracking and water uptake. The dry grout contains 35 wt% to 45 wt% white CEM I 52.5 R, 50 wt% to 60 wt% quartz sand below 0.2 mm, 0.5 wt% to 1.5 wt% calcium carbonate filler, 0.1 wt% to 0.3 wt% cellulose ether, and 0.05 wt% to 0.15 wt% of a powdered hydrophobic agent. The material is mixed to a stiff paste and worked into the joint with a rubber float; joints wider than 5 mm are packed in layers to avoid air pockets. Water absorption after immersion and flexural strength are tested under EN 13888:2017 for CG2-class grouts with enhanced properties. Field failures in this segment are usually caused by excessive water addition on site, which increases shrinkage and opens hairline channels through the grout. The terminal installation is the tile joint in a pool shell or water feature containment, where the grout must remain impermeable under a permanent water head.
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Flexible RDP for waterproofing mortars is a spray-dried redispersible polymer powder based on a vinyl acetate-ethylene/vinyl ester terpolymer. It is stabilized with a polyvinyl alcohol protective colloid and surface-treated with a mineral anti-caking agent to maintain free-flowing behaviour during storage and dry blending. The material is specified by its thermomechanical profile rather than by a single manufacturer designation: glass transition temperature -15 °C to -5 °C when measured by differential scanning calorimetry in accordance with ISO 11357-2, minimum film formation temperature ≤5 °C by ISO 2115, and redispersed pH 6.0–8.5 by ISO 976. Residual moisture is controlled to ≤2.0 wt% to limit lumping in dry-mix silos.
The powder is designed for dry incorporation into one-component cementitious waterproofing slurries and two-component flexible membranes. During mixing with water, the protective colloid dissolves and the polymer particles redisperse to a latex with a volume-average particle size typically 1–10 µm. The flexible grade differs from standard rigid VAE powders by its lower glass transition temperature and higher free-film elongation at break, which is commonly reported between 300% and 600% under ISO 527-2 at 23 °C and 50 mm/min.
| Property | Typical range | Test basis |
|---|---|---|
| Appearance | White to off-white free-flowing powder | Visual |
| Bulk density | 450–650 g/L | DIN EN ISO 60 |
| Residual moisture | ≤2.0 wt% | ISO 787-2, 105 °C |
| Ash content | 8–12 wt% at 450 °C | ISO 3451-1 |
| pH of redispersion | 6.0–8.5 | ISO 976 |
| Glass transition temperature | -15 to -5 °C | ISO 11357-2 |
| Minimum film formation temperature | 0–5 °C | ISO 2115 |
| Wet sieve residue on 63 µm | ≤2.0 wt% | Manufacturer method, 63 µm screen |
The principal distinction is the ethylene/vinyl ester ratio and the resulting glass transition temperature. Rigid VAE grades with Tg values of +5 °C to +15 °C produce polymer films with tensile strength in the range of 8–15 MPa and elongation at break of 10–60%. Flexible waterproofing grades with Tg values of -15 to -5 °C exhibit lower tensile strength, generally 3–8 MPa, but elongation at break of 300–600%. In a hydrating cement matrix, the flexible polymer bridges microcracks formed by drying shrinkage, thermal movement, and early-age loading. The rigid grade cannot accommodate the same strain without cracking and therefore reduces membrane watertightness once the cement phase is cracked.
Compared with liquid styrene-butadiene rubber dispersions, the flexible RDP offers one-component dry-mix packaging, storage without preservative or freeze-thaw liquid management, and lower freight mass. Liquid SBR dispersions may show higher elongation at break, often 400–800%, but require controlled storage above freezing and can generate additional air entrainment in mortars if not defoamed. Compared with acrylic or acrylic ester powders, the flexible VAc/VeoVa/E terpolymer provides a more favourable balance of alkaline hydrolysis resistance and cement compatibility, although it is not intended to replace two-component epoxy or polyurethane systems in permanent immersion conditions.
| Attribute | Flexible RDP (Tg -15 to -5 °C) | Rigid VAE RDP (Tg +5 to +15 °C) | Liquid SBR dispersion |
|---|---|---|---|
| Polymer film elongation at break | 300–600% per ISO 527-2 | 10–60% per ISO 527-2 | 400–800% per ISO 527-2 |
| Packaging format | One-component dry mix | One-component dry mix | Two-component liquid/powder |
| Storage freeze-thaw risk | None in sealed dry storage | None in sealed dry storage | Liquid freezes below 0 °C |
| Air entrainment tendency | Low to moderate; requires defoaming strategy | Low | Moderate to high |
| Use in permanent immersion | Not recommended without protective topcoat | Not recommended | Not recommended without protective topcoat |
In dry-mix plants, the flexible RDP is added to cement, graded silica sand, cellulose ether, and defoamer through a loss-in-weight feeder upstream of a ribbon blender or ploughshare mixer. The powder should not be introduced into the mixer after the liquid additives because localized agglomeration and screen tailings increase. Batch-to-batch variation in bulk density, typically ±30 g/L, can produce stratification in pneumatic conveying lines if the conveying velocity falls below the saltation velocity of the coarse mineral fraction. On a 500–1000 kg horizontal ribbon blender, a mixing time of 180–240 s at 25–35 rpm is used to reach a coefficient of variation below 5% for RDP distribution. Sampling at the discharge chute should include the first and last 10% of the batch to monitor segregation at the packer.
The mixed powder is discharged into moisture-barrier bags with an internal polyethylene liner. Storage in open silos at relative humidity above 60% is not recommended because the protective colloid is hygroscopic and may initiate caking. The product should be stored at 5–35 °C and used within 12 months of manufacture when kept in unopened bags.
The redispersed polymer at 50 wt% solids exhibits shear-thinning behaviour with a Brookfield RVT viscosity of 200–1000 mPa·s at 20 °C and 20 rpm, spindle 4. Addition of the flexible RDP to a cementitious slurry at 3.0–6.0 wt% of total dry mortar reduces the yield stress and plastic viscosity relative to an unmodified mortar, but air entrainment from the protective colloid can lower wet density by 5–15%. In forced-action mortar mixers running at 400–600 rpm, the slurry temperature should be monitored because frictional heating above 35 °C accelerates cement hydration and lowers open time. High-shear dispersion above 800 rpm is generally unnecessary and can raise air content above 8%, reducing compressive strength and increasing dry shrinkage.
For continuous in-line mixing of two-component formulations, a loss-in-weight screw feeder delivering the powder component into a high-shear pin mixer is preferred over a simple paddle tank because it shortens the wetting time of the polymer and breaks down undispersed clusters. The powder feed rate is set to maintain 0.20–0.25 water-to-mortar ratio, with the mixing chamber vacuum-deaerated to keep air content below 5%. If the air content exceeds 7%, a liquid defoamer based on mineral oil or silicone is added at 0.1–0.3 wt% of the mix water, but excessive defoamer can impair polymer film coalescence and reduce tensile adhesion.
Flexible cementitious waterproofing membranes containing the RDP are tested for water impermeability and crack-bridging capacity under EN 14891:2017. The test substrate is a concrete slab or fibre-cement panel conditioned at 23 °C and 50% RH. The mixed slurry is applied in two coats to a total dry-film thickness of 1.5–2.0 mm and cured for 28 days before testing. The crack-bridging test introduces a controlled crack opening at a defined rate while the membrane is subjected to static water pressure. Formulations with flexible RDP at 3–6 wt% of total dry mix are typically reported by suppliers to bridge crack widths of 0.5–2.0 mm at 20 °C; published data for this specific configuration is limited, and project-specific validation is required because crack-bridging performance is also controlled by substrate stiffness, coat thickness, curing conditions, and polymer dosage.
Dynamic crack-bridging testing may alternatively follow EN 1062-7 for coating materials, where the membrane is applied over a precracked block and the crack is cycled at a defined rate and displacement. Tensile adhesion of the cured membrane to concrete is measured by pull-off in accordance with EN 1542. Typical cementitious flexible waterproofing formulations achieve values of ≥1.0 MPa after 28 days dry cure, with failure occurring cohesively in the substrate or membrane rather than at the bond line. After immersion in water for 7 days, adhesion decreases but should remain above 0.5 MPa in well-cured flexible RDP-modified mortars. For low-temperature service, membrane flexibility can be evaluated by bending a 1.5 mm cured film over a mandrel at -10 °C; flexible RDP formulations resist cracking under these conditions, whereas rigid VAE grades fail by brittle fracture.
Application of the flexible RDP-modified waterproofing slurry is performed after mechanical cleaning of the substrate and pre-wetting to saturated surface dry condition. The dry mortar is mixed with clean water at a water-to-mortar ratio of 0.20–0.25 by weight using a low-RPM paddle mixer at 400–600 rpm for 2–3 minutes, then left to slake for 3–5 minutes, and remixed for 30 seconds. The mixed slurry is applied by trowel or brush at a wet-film thickness of 1.0–2.0 mm per coat, with the second coat applied at right angles after the first coat has hardened. Consumption is typically 1.5–2.5 kg/m²/mm dry thickness. The polymer film forms during cement hydration and drying; full flexibility is reached only after the free water has escaped and the minimum film formation temperature is exceeded during curing.
Property response to dosage is not linear. At flexible RDP additions below 2.0 wt%, the cementitious matrix dominates, and the cured membrane shows tensile adhesion below 0.5 MPa and crack-bridging capacity below 0.25 mm. As dosage increases to 3.0–4.0 wt%, the dry density decreases, and elongation of the polymer-modified matrix increases rapidly. Above 6.0 wt%, the slurry becomes sticky, open time shortens, and compressive strength at 28 days can fall below 20 MPa, which may be unacceptable for tile-over applications. The processing window is therefore commonly maintained at 3.0–5.0 wt% for flexible waterproofing membranes. The exact optimum varies with cement type, water-to-cement ratio, and aggregate grading, and must be confirmed by factorial trials on the actual production formula.
Water-to-mortar ratio is a critical threshold variable. An increase of 0.02 in water-to-mortar ratio beyond the recommended 0.25 can reduce tensile adhesion by 20–40% and extend the membrane drying time by more than 24 h at 10 °C and 70% RH. Conversely, water ratios below 0.20 produce a stiff slurry that does not wet the substrate uniformly, leaving pinholes and unhydrated cement pockets. In automatic continuous mixing, water dosing is controlled by mass flow meters with accuracy of ±0.5%; in manual mixing, the water is weighed rather than volume-dosed to avoid density-related error. At 23 °C and 50% RH, the first coat reaches touch-dry state in 2–4 h; the second coat should not be applied until the first coat is firm enough to resist brush drag but still moist to allow mechanical keying. Full polymer film coalescence in thick membranes may require 7–14 days under cool, humid conditions. If the membrane is exposed to rain before 24 h of curing, washout of the uncoalesced polymer can occur, reducing final water impermeability.
Operational boundaries apply. The flexible RDP-modified cementitious slurry is not suitable for permanent hydrostatic pressure conditions without an elastomeric topcoat or waterproofing system design that isolates the membrane from continuous water immersion. Contact with acidic or sulfate-rich groundwater below pH 5.0 may degrade the cement matrix and is not addressed by the polymer modification alone. The product should not be combined with high-alumina cement or calcium aluminate accelerators because rapid heat evolution and pH shifts can coagulate the redispersed polymer before film coalescence. Solvent-based adhesion promoters should be avoided in the same mix because they may interact with the protective colloid and inhibit redispersion.
Quality control of incoming flexible RDP shipments should include redispersion viscosity, sieve residue, bulk density, and moisture content. A batch-to-batch viscosity variation of more than ±20% at 50 wt% solids indicates colloid degradation or storage damage. The powder is accepted only if the 63 µm wet sieve residue is below 2.0 wt% because larger skins or agglomerates produce fisheyes in the cured membrane. In automated dry-mix plants, near-infrared moisture sensors may be installed at the mixer outlet to reject batches above 0.3% moisture before packing; such limits are common in silo storage and reduce the risk of in-bag hydration. For REACH compliance, the powder is supplied as a polymer preparation; the manufacturer’s safety data sheet should be checked for residual monomer, preservative, and dust exposure limits. In the European Union, the dry-mix containing the RDP must be evaluated for airborne dust under the Construction Products Regulation and for volatile organic compound content under indoor air regulations where applicable. The powder contains no intentionally added formaldehyde donor in standard flexible waterproofing grades; however, the protective colloid and anti-caking agent must be disclosed in the safety data sheet for occupational exposure assessments.
