Epoxy-Modified Waterborne Polyester Resin for Coil & Tape

WQ-PR436 is a medium molecular weight, epoxy-modified branched resin with excellent coating film performance. The coating film offers outstanding adhesion and hardness, high gloss, good scratch resistance, and a good balance between hardness and flexibility. It is mainly used in waterborne tape measure coatings, waterborne coil coatings, waterborne packaging coatings, waterborne glass coatings, and other fields.

• Extremely low VOC, environmentally compliant, low explosion-proof requirements for production lines, can be cleaned with water.
• Low odor, meets RoHS requirements for exports.
• Excellent film flexibility, suitable for subsequent stamping and bending of coil stock.

The biggest characteristic of coil stock is short-time high-temperature baking, measured as PMT (peak metal temperature).

• Coating method: two-roll reverse coating, high-speed roll coating (100–200 m/min).
• Dry film thickness: primer 5–8 μm; topcoat 18–25 μm; backcoat 8–12 μm.
• Baking: PMT 180–230°C, 20–80 seconds (instantaneous peak temperature of the metal sheet, not the oven temperature).
• Key difficulty: water has a high latent heat of vaporization, so the oven zones must be temperature-controlled in stages — first low-temperature pre-evaporation, then high-temperature crosslinking. Otherwise, pinholes, blistering, and solvent popping are highly likely. This is the most common defect in water-based coil coatings.
• pH control: system pH 7.5–8.5, commonly neutralized with DMEA (dimethylethanolamine).

Water-based UV absorbers can be added to make an outdoor weatherable version. For dark colors, infrared-reflective pigments can be used to make heat-insulating coil coatings.

• Water-based industrial baking coatings: hardware fittings, chassis and cabinets, aluminum component decorative topcoats.
• One-coat light-duty anticorrosive coatings (indoor environments).