1. Product Introduction

Redispersible Polymer Powder (RDP), also known as redispersible emulsion powder or dry-mix adhesive powder, is typically produced by spray-drying a vinyl acetate-ethylene (VAc-E / VAE) copolymer emulsion in the presence of a protective colloid such as polyvinyl alcohol (PVA). It is a white to off-white, free-flowing powder that readily redisperses in water to reconstitute a stable emulsion. After water evaporation, the polymer forms a coherent film that imparts adhesion, flexibility and pore-blocking effects to cementitious or gypsum-bound matrices. RDP is therefore the essential organic binder and modifying component in dry-mix mortars.

By polymer base: VAE (vinyl acetate-ethylene), VAc-VeoVa, acrylic, SBR (styrene-butadiene) and terpolymers. By glass-transition temperature (Tg): rigid (high Tg), semi-flexible, flexible and hydrophobic grades, selected according to the required mechanical response and water resistance.

 

2. Key Features & Advantages

• Markedly improves adhesion and cohesion:

◦ The polymer film builds strong bond bridges across dissimilar substrates (concrete, masonry, EPS/XPS boards, tiles, etc.), especially on smooth or low-absorption surfaces.

• Excellent flexibility and deformability:

◦ Lowers the elastic modulus while increasing flexural strength, absorbing thermal and shrinkage stresses and thus suppressing cracking.

• Better workability:

◦ Improves flow, thixotropy and sag resistance, extends the open time and enhances water retention and trowelability.

• Weathering, freeze-thaw and durability:

◦ The thermoplastic polymer film relaxes with temperature changes, resists freeze-thaw cycling, reduces carbonation depth and extends service life.

• Hydrophobicity and reduced water uptake:

◦ Films seal pores and capillary pathways; specialised hydrophobic grades impart pronounced water repellency and impermeability.

• Higher abrasion, impact resistance and density:

◦ Polymer particles fill voids, increasing density, abrasion resistance and impact strength.

• Convenient storage and transport:

◦ Can be dry-blended and dosed together with other powder raw materials, eliminating on-site emulsion preparation and supporting automated, standardised production.

 

  3. Main Technical Parameters

Typical technical data for a general-purpose VAE grade (reference values, not part of the supply specification; always refer to the TDS / COA of the specific grade).

Item	Typical Value	Test Note
Appearance	White / off-white free-flowing powder	Uniform colour, no lumps
Solids Content	≥ 98.0 %	Loss on drying, 105 ℃
Ash Content(1000 ℃)	10 ± 2 %	Grade-dependent, 8–18 %
Bulk Density	300–600 g / L	Grade-dependent
Protective Colloid	PVA	—
pH 值 (50% )	6 – 9	DIN / ISO
Tg	-15 ~ +15 ℃	DSC; grade-dependent
MFFT	0 – 5 ℃	ISO 2115
Particle Size	≤ 4 % > 400 μm	Sieve residue / laser diffraction
40  Sieve Residue	≤ 2.0 %	—
50%  Viscosity	0.5 – 10 Pa·s	Brookfield
Film	Semi-transparent, flexible	Semi-transparent, flexible
CAS / EINECS	24937-78-8 / 429-840-1	VAE

 

Note: Ash, bulk density, Tg, MFFT and particle size vary substantially with rigid / flexible / hydrophobic grade; select against the grade-specific TDS.

 

 4. Usage Requirements

Dosage:

•Generally 0.5%–3.0% by mass of total dry powder, commonly 1.0%–2.0%; a typical addition is 10–20 kg per tonne of dry mix. Determine by trial in the actual formulation.

 

Typical reference dosage:

•Tile adhesive 0.8%–2.5%; tile grout 1.0%–2.0%; ETICS / EIFS bonding mortar 0.5%–1.5%; water-resistant putty 1.0%–3.0%; interface agent 0.3%–0.5%; inorganic thermal mortar 0.3%–1.0%.

 

Mixing method:

• Dry blending: homogenise the powder with other dry raw materials (cement, sand, fillers, HPMC, etc.) before adding water.

• Add water per mix design and stir thoroughly with a mortar mixer until lump-free; a 3–5 min maturation followed by re-mixing is recommended.

• Observe the water-to-powder ratio and mixing temperature prescribed for the mortar system; use water fit for concrete/mortar mixing.

 

Compatibility:

• Compatible with cement, gypsum, silica sand, calcium carbonate, cellulose ethers (HPMC) and common dry-mix additives; avoid prolonged blending with strong acids, strong alkalis or aggressive solvents.

 

 5. Precautions

• Moisture protection:

◦ Hygroscopic product — use soon after opening and keep sealed. Caked or discoloured material indicates degradation; do not reuse.

• Storage environment:

◦ Keep away from direct sunlight, rain, high temperature, heat and open flame. Application temperature preferably ≥ 5 ℃; below the MFFT, film formation is impaired.

• Dispersion and film formation:

◦ Ensure thorough dry blending and adequate mixing time to avoid undispersed “fish eyes”; the dried polymer film will not redisperse or leach out.

• Safe handling:

◦ Wear a dust mask, protective gloves and goggles; avoid inhalation of dust and eye contact. Read the MSDS / SDS before use.

• Validation:

◦ Performance varies with cement, sand source, additives and application conditions; conduct mix-design trials and on-site tests before full-scale or formula-changing production.

• Restriction:

◦ Non-edible chemical — not for use in food, pharmaceutical or potable-water contact applications.

 

 6. Packaging & Storage

Packaging:

Normally multi-ply paper bags with a polyethylene (PE) inner liner, or film-laminated woven bags, 25 kg net per bag. Ton bags (~500–1000 kg) or palletised packaging (~600–1300 kg / pallet) are available on request.

Storage conditions:

Seal and store in a cool, dry, well-ventilated place, protected from moisture, sunlight, rain and high temperature. Stack within the stated pallet height and avoid crushing the bags.

Shelf life:

Under original, unopened and proper storage conditions, the recommended shelf life is generally 6–12 months (per grade TDS); beyond this, use only after passing inspection.

Transport:

Transport as ordinary chemical goods, moisture- and rain-proof; do not ship together with strong acids, strong alkalis or corrosive substances.

 

7. Scope of Application

 

• External thermal insulation composite systems (ETICS / EIFS): bonding mortar and rendering mortar over EPS / XPS / rock wool boards.

• Tile adhesives and tile grouts.

• Self-levelling and flooring / wear-resistant mortars.

• Interior / exterior flexible and water-resistant putty, dry-mix coatings, decorative and diatomaceous mortars.

• Flexible anti-crack, repair and waterproof mortars; interface agents / bonding slurries.

• EPS-bead thermal mortars, inorganic thermal mortars, masonry mortars and powder adhesives.