When you’re sourcing redispersible polymer powder (RDP) for tile adhesive, EIFS base coat, self-leveling compound, or repair mortar, the difference between a high-performing batch and a substandard one can cost you customer complaints, failed lab trials, and rejected shipments. Yet many procurement teams rely solely on a supplier’s Certificate of Analysis (CoA) without understanding what the numbers actually mean — or whether they’ve been tested to the right standards.
This guide walks through every critical quality parameter for RDP, explains the accepted test methods, and shows how MikaVAE® grades from Michem Chemical Co., Ltd. map to each specification — so you can make informed sourcing decisions and build a robust incoming-QC protocol.
RDP is the most expensive single ingredient in most dry-mix mortar formulations — typically 1–6% by weight but 20–40% of total raw-material cost. A batch that deviates from spec can cause:
A structured QC programme catches these issues at the receiving dock — not after they’ve reached your customer’s jobsite.
| 参数 | 规格 | 测试方法 |
|---|---|---|
| 固体内容 | ≥ 99% | Oven drying at 105°C × 2 h, gravimetric |
| Residual moisture | ≤ 1% | Same as above |
Why it matters: RDP is spray-dried to a powder. If residual moisture is too high, the powder cakes in storage, flows poorly through dosing equipment, and has a shorter shelf life. A solid content below 99% also means you’re paying for water.
Michem specification: All grades (5010R, 5030FN, 5034H, 5002T) guarantee solid content ≥ 99%.
Ash content indicates the level of inorganic anti-caking agent (typically kaolin or calcium carbonate) added during spray-drying. It directly correlates with the effective polymer content — the portion that actually forms a film and contributes to adhesion and flexibility.
| Michem Grade | 灰分含量 | Effective Polymer | Primary Application |
|---|---|---|---|
| 5010R | 14 ± 2% | ~84–86% | Tile adhesive C1/C2, general-purpose |
| 5030FN | 12 ± 2% | ~86–88% | Flexible tile adhesive, repair mortar |
| 5034H | 12 ± 2% | ~86–88% | Waterproofing, EIFS base coat |
| 5002T | 12 ± 2% | ~86–88% | Self-leveling, high-flexibility systems |
Test method: Muffle furnace at 950°C × 2 h until constant weight (ISO 3451-1 or EN ISO 24937-based).
QC alert: If ash content is significantly higher than specified, the supplier may be over-loading filler to reduce cost — diluting the active polymer and degrading performance. If it’s too low, the powder may cake excessively during transport and storage.
Tg determines the minimum film-forming temperature and the flexibility/hardness balance of the cured polymer film.
| Michem Grade | 聚合物类型 | Tg |
|---|---|---|
| 5010R | VAE (vinyl acetate / ethylene) | 15 °C |
| 5030FN | VAE | 15 °C |
| 5034H | VAE | 15 °C |
| 5002T | VA / E / VV (vinyl acetate / ethylene / vinyl versatate) | 10 °C |
Test method: DSC (Differential Scanning Calorimetry), ASTM E1356 or ISO 16805.
How to interpret: A Tg of 10–15 °C means the polymer film is soft and flexible at ambient temperature — ideal for tile adhesives that must accommodate thermal movement and substrate deflection. Harder grades (Tg ≥ 25 °C) exist in the market but are less common in construction applications; they produce stiffer, more brittle films.
QC alert: Tg that drifts more than ±2 °C from spec indicates a formulation change or raw-material substitution at the supplier’s plant. This will alter the flexibility and crack-bridging performance of your mortar.
MFFT is the lowest temperature at which the polymer particles coalesce into a continuous, defect-free film. Below MFFT, the film is cracked, powdery, and non-functional.
| 参数 | 规格 |
|---|---|
| MFFT | 4 °C (all Michem grades) |
Test method: MFFT bar apparatus (ASTM D2354 / ISO 2115).
Why it matters: A low MFFT (4 °C) means the RDP will form a proper film even in cool-weather application — critical for outdoor construction in temperate climates or GCC winter-night conditions. If MFFT rises (e.g., to 10 °C or higher), early-spring or late-autumn applications in Europe and Central Asia will produce poor films.
| 参数 | 规格 |
|---|---|
| 体积密度 | 400–600 g/L |
Test method: Scott volumeter or tapped bulk density (ISO 60 / ASTM B417 for powders).
Why it matters: Bulk density affects packaging, dosing accuracy in automated lines, and mortar bulk density. A sudden shift indicates changes in spray-drying parameters or particle morphology.
| 参数 | 规格 |
|---|---|
| pH (10% aqueous dispersion) | 6–8 |
Test method: pH meter on 10% aqueous dispersion at 25 °C (ISO 976).
QC alert: pH outside 6–8 can indicate residual acidity from incomplete neutralisation during polymerisation, which may interfere with cement hydration and setting time.
This is the most application-relevant test — and the one most often skipped by buyers.
Procedure:
Pass criteria: < 0.5% retained on sieve; continuous, transparent, crack-free film.
| 财产 | 5010R | 5030FN | 5034H | 5002T |
|---|---|---|---|---|
| 聚合物类型 | VAE | VAE | VAE | VA/E/VV |
| 固体内容 | ≥ 99% | ≥ 99% | ≥ 99% | ≥ 99% |
| 灰分含量 | 14 ± 2% | 12 ± 2% | 12 ± 2% | 12 ± 2% |
| Tg | 15 °C | 15 °C | 15 °C | 10 °C |
| MFFT | 4 °C | 4 °C | 4 °C | 4 °C |
| pH | 6–8 | 6–8 | 6–8 | 6–8 |
| 体积密度 | 400–600 g/L | 400–600 g/L | 400–600 g/L | 400–600 g/L |
| CAS No. | 24937-78-8 | 24937-78-8 | 24937-78-8 | 24937-78-8 |
| HS 编码 | 39052900 | 39052900 | 39052900 | 39052900 |
Laboratory CoA data tells you the powder is within spec — but not how it performs in your mortar. A robust QC protocol should include application-level tests on incoming material:
Prepare a standard C2 tile adhesive formulation with the new RDP batch. Measure tensile bond strength after 28 days standard curing + 14 days water immersion. Compare against your historical baseline.
| Performance Level | Dry (MPa) | Wet (MPa) | Heat-aged (MPa) |
|---|---|---|---|
| EN 12004 C1 | ≥ 0.5 | ≥ 0.5 | ≥ 0.5 |
| EN 12004 C2 | ≥ 1.0 | ≥ 1.0 | ≥ 1.0 |
| Premium (target) | ≥ 1.5 | ≥ 1.2 | ≥ 1.3 |
Measure transverse deformation of a polymer-modified mortar prism (40 × 40 × 160 mm) under four-point bending. S1 ≥ 2.5 mm; S2 ≥ 5.0 mm.
For waterproofing and EIFS applications, test the ability of the RDP-modified coating to bridge a substrate crack at various temperatures.
| Step | Action | Frequency |
|---|---|---|
| 1 | Request full CoA with every shipment (not just first batch) | Every shipment |
| 2 | Verify solid content, ash content, pH on random samples | Every 5th shipment or monthly |
| 3 | Perform redispersibility check | Every shipment |
| 4 | Run application-level bond strength test | Every new lot or quarterly |
| 5 | Retain 500 g sample in sealed bag for 12 months | Every shipment |
| 6 | Track all data in a trend chart; investigate any deviation > 2σ | Continuous |
Some suppliers increase the anti-caking agent to 20% or more, reducing the effective polymer content while maintaining the same price per kg. Always check ash content against the stated grade spec.
A supplier may switch from VAE (vinyl acetate / ethylene) to a cheaper VAc/versatate or styrene/acrylic copolymer without notification. DSC and FTIR analysis can detect this. Michem grades use genuine VAE or VA/E/VV terpolymers — never undisclosed substitutions.
Overly fine particles (< 50 μm) create dust and poor flow; coarse particles (> 300 μm) dissolve slowly and leave grit in the mortar. Laser diffraction (ISO 13320) should show a D50 of 80–150 μm for optimal performance.
RDP is hygroscopic. Even within-spec product can degrade if stored in high-humidity warehouses. Check packaging integrity (multi-wall paper bag with PE inner liner) and verify storage conditions (dry, < 30 °C, < 60% RH). Recommended shelf life: 12 months from manufacture date under proper conditions.
Effective RDP quality control is not about running every possible test on every shipment — it’s about knowing which parameters matter most for your application, verifying them consistently, and building a trend-tracking system that flags deviations before they become field failures.
For tile adhesive manufacturers, ash content and bond-strength performance are paramount. For waterproofing and EIFS, Tg and crack-bridging behaviour dominate. For self-leveling compounds, redispersibility and particle size are the critical gates. By aligning your QC protocol to your end-use, you protect both your production efficiency and your brand reputation.
Michem — the RDP/VAE polymer powder brand of Michem Chemical Co., Ltd. — provides four clearly differentiated grades (5010R, 5030FN, 5034H, 5002T) with consistent, documented specifications. Full CoAs, technical data sheets, and application support are available on request.
Contact the Michem Technical Team at michemicals.com/contact for:
Michem is the RDP/VAE redispersible polymer powder brand of Michem Chemical Co., Ltd. Other products — HPMC cellulose ether, polycarboxylate superplasticizer, calcium formate, and TenaBrix® polypropylene fiber — are marketed under their respective brands.
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