1 Part D4 wood adhesive | Exterior Joinery, pva glue

Supex 1 Part D4 Wood Adhesive

A 1-part cross-linking PVAc D4 dispersion is a ready-to-use, water-based wood adhesive that achieves EN 204 Class D4 water resistance without adding an external hardener. Upon drying, internal chemical cross-linking forms a durable, weatherproof, heat-resistant bond, making it ideal for exterior doors, windows, and heavy joinery.

Best suited for rapid industrial joinery, HF/RF presses, laminating, and door/window scantling.

Specification Property	Technical Value / Standard
Chemical Base	Water-based self-crosslinking PVAc (Polyvinyl Acetate) emulsion
Water Resistance Class	EN 204 D4 & WATT 91 heat resistance
Appearance / Color	Milky white / off-white liquid (dries clear)
Solid Content	44% – 48%
pH Value	3.0 – 3.8 (mildly acidic)
Density	Approx. $1.07\text{ g/cm}^3$
Viscosity	5,000 – 6,500 mPa·s (at 20°C, Brookfield)
Open Time	8 – 10 minutes (at 20°C, 150 g/m²)
Minimum Clamping Time	15 – 25 minutes (at 20°C)
Press Pressure	0.2 – 0.6 N/mm²
Coverage	150 – 180 g/m² (assembly), 80 – 140 g/m² (surface)
Minimum Film Forming Temp (MFFT)	Approx. +8°C to +10°C

EN 204 Classification Benchmark (What D4 Means)

Dry Interior: Maintains structural bond strength ( $\ge 10\text{ N/mm}^2$ ).
Water Soak: Endures 7 days of cold water immersion + 6 hours in boiling water while maintaining strong cohesive failure without delaminating.
Intended Use: Exterior woodwork exposed directly to weather, coastal humidity, bathroom/kitchen cabinetry, and cold storage structural sandwich panels.
Pressing Times (Guide Values)
- Cold Press (20°C): ~15 to 25 minutes (dependent on wood species and moisture)
- Warm Press (50°C): ~3 to 5 minutes
- Hot Press (70°C): ~1 to 2 minutes
- Radio Frequency (HF Press): Often $< 1\text{ minute}$ depending on power output
Key Processing Guidelines
- Wood Moisture: Ideal range is 8% to 12%. Moisture above 15% can weaken the bond and extend press times significantly.
- Tannin-Rich Woods: Due to its acidic pH (~3.0–3.5), it can react with iron and tannin-rich woods (such as Oak, Beech, or Chestnut) to cause slight dark staining. Avoid using iron fittings or applicator tips; use stainless steel (V2A/V4A) or plastic.
- Post-Press Curing: Although components can be machined shortly after pressing, maximum D4 water resistance develops after 7 days of full cross-linking.
- Storage & Shelf Life: Store between +10°C and +25°C. Keep protected from frost (freezing destroys the emulsion). Typical shelf life is 9 months unopened.