720A 720B Polyurethane Dry Lamination Adhesive with High Peeling Strength Tunnel Prevention and FDA 175.105 Compliance for Film Foil Laminates
Product Overview
Weeton 720A/720B is a two-component polyurethane adhesive for film/film and film/foil laminates delivering high peeling strength and good transparency. Its balanced rheology effectively prevents the tunnel phenomenon, ensuring a clean, uniform appearance in printed and unprinted flexible packaging.
Key Features
- Effectively prevents tunnel phenomenon in lamination
- High peeling strength for durable laminate bonds
- Good transparency for clear film applications
- High initial adhesion for immediate line stability
- FDA 175.105 compliant for food contact laminates
- Adjustable dilution (30-45% solid content) for process flexibility
Applications
- Transparent film/film lamination for clear pouches
- Film/foil laminates for barrier packaging
- Printed laminates requiring precise adhesive laydown
- Food packaging dry lamination lines
Typical Technical Parameters
| Parameter | Specification |
|---|---|
| Composition | Two-component polyurethane (720A + 720B) |
| Mixing Ratio | 20:4 (mass ratio) |
| Solid Content | 72 +/- 2% (A) / 75 +/- 2% (B) |
| Viscosity (25C) | 4500 +/- 500 mPa.s (A) / 2000 +/- 1000 mPa.s (B) |
| Solvent | Ethyl acetate |
| Coating Weight | 2.0 - 3.2 g/m2 (dry) |
| Pot Life | About 8 hours |
| Curing | 40-50C for 24 h |
| Compliance | FDA 175.105 |
| Packing | 720A: 20KG/bucket; 720B: 4KG/bucket |
Directions for Use & Precautions
- Dilute 720A with ethyl acetate (water below 300 ppm) before adding 720B.
- Never use aromatic or alcoholic solvents for dilution.
- Consume the ready-for-use adhesive within 8 hours; max 4 hours retention in the machine.
- In tropical conditions use within 2 hours to avoid unstable lamination.
- Add approximately 0.5-1 g/m2 more adhesive for printed films.
- Follow isocyanate handling regulations and install exhaust hood on the coating unit.
FAQ
Q: How does 720A/720B prevent tunnel phenomenon?
A: Its balanced viscosity and excellent wetting behavior allow uniform adhesive laydown and smooth film lamination, effectively preventing tunnel phenomenon.
Q: Is 720A/720B transparent after curing?
A: Yes, the cured adhesive layer provides good transparency, making it suitable for clear film laminates.
Q: What solid content should I use?
A: The dilution table supports solid contents from 30% to 45% depending on the required viscosity and coating performance.
Q: Does 720 comply with food regulations?
A: Yes, 720 is in compliance with FDA 175.105.
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