Precautions for Direct Coating Water-based PSA

Dear Customer,

Thank you for choosing our water-based PSA product.

This adhesive is an acrylic emulsion, non-hazardous, with low VOC content. It is more environmentally friendly and safer for operators’ health, while maintaining bonding strength and heat/humidity resistance comparable to traditional solvent-based PSAs.

On Odor

Low VOC does not necessarily mean low odor.

Even water-based PSAs have a certain level of odor. Perception of odor varies among individuals due to differences in olfactory sensitivity. For customers with low-odor requirements, please ensure good workshop ventilation after coating, and avoid storing PSAs together with other solvent-based or odorous materials in the same space.

On Solid Content & Viscosity

Our water-based PSAs are generally supplied in high-solid form (≥50% solids) to suit coating lines of various lengths and heating conditions. This helps reduce energy consumption, lower water content, and shorten drying time.

• Typical RT viscosity: 10,000 – 25,000 mPa·s
• Suitable for:
  • Oven length: 16 – 30 m
  • Wet coating weight: 80 – 200 g/m²
  • Line speed: 3 – 20 m/min

If your oven length, coating weight, or line speed exceeds these ranges, please inform us so we can adjust the viscosity to ensure coating compatibility.

Key Coating Considerations

1. Five critical coating variables: temperature profile, coating speed, air in/out volume, lamination pressure, curing time.
   • These must be adjusted based on oven length, heating power, coating weight, substrate type, and adhesive performance requirements.
   • If you are using our PSA for the first time, please inform us of your equipment specifications (length, heating method) so we can recommend optimal coating parameters.
2. Drying principle: Water-based PSAs dry by water evaporation.
   • Air volume balance is often overlooked. Insufficient dehumidification may lead to high moisture concentration inside the oven, causing condensation or poor drying efficiency.
3. Dry adhesive lamination:
   • Prefer two-step lamination:
     • Step 1: Pre-lamination (light pressure to exhaust air and smooth surface)
     • Step 2: Final lamination (higher pressure to enhance penetration and adhesion)
   • One-step lamination may cause material deformation or thickness reduction, leading to shrinkage after die-cutting.
4. Glue pan handling:
   • Keep liquid level 1 cm below the baffle to avoid roller–baffle friction that generates heat and dried gel particles, which may block the doctor blade and cause line defects.
   • Periodically spray ~75% ethanol at the baffle edges to reduce bubbles and dried particles.
5. Curing time:
   • Adhesive strength improves with curing.
   • 24 hours: good adhesion
   • 72 hours: stable adhesion
   • For low-density foams without release liners, avoid multi-layer die-cutting, as adhesive penetration may cause “loss of tack.”
6. Release liner precautions:
   • Paper liners with single-side PE/silicone coatings may warp under high humidity, causing delamination. Ensure proper dehumidification.
   • Under very dry conditions, ensure re-moisturizing to prevent liner curling or strong static buildup.

Adhesive Storage

• Store at 0–40℃.
• Use within 6 months for best performance.
• After opening, seal tightly to prevent surface skinning.
• If additives are introduced or the adhesive is altered without our consent, we will not be responsible for quality issues.

Manual Application Notes

1. Temperature control:
   • Ensure workshop temperature is above 10℃.
   • Substrate temperature must not be below 9℃.
2. Surface preparation:
   • Metal parts: free from oil, condensation, or coolant.
   • Plastic parts: free from mold-release agents.
3. Manual bonding:
   • Apply a lamination pressure of at least 100 gf/cm².
   • Cold press dwell time: ≥1 second (longer is better).