SiwoPUD®-U-679

Polycarbonate-Based Polyurethane Dispersion with Excellent Hydrolysis and Aging Resistance

Characteristics:

It is also based on polycarbonate waterborne polyurethane, similar to U-678.

Key Spec​:

Solids Content:

50% in water

Appearance:

Milky white

Minimum film-forming temperature:

5℃

Minimum activation temperature:

120-130℃

Yellowing resistance:

Non- yellowing

PH Value:

6.0– 9.0

Storage:

The dispersion should be stored in a frost-free place in tightly sealed containers. It contains no preservative.

Packaging:

500 G/1 KG bottle, 200 KG plastic drum, 1 MT container

Application:

SiwoPUD®-U-679 is an anionic, high-molecular-weight, non-crystalline, polycarbonate-based waterborne polyurethane dispersion developed for high-performance heat-activated polyurethane adhesives. It provides excellent flexibility, initial tack, anti-blocking properties, and high bonding strength, with strong adhesion to a wide range of synthetic and natural materials.

U-679 is suitable for heat-activated bonding, semi-dry bonding, and wet bonding applications involving fabrics, leather, packaging materials, and other substrates. Compared with U-658 and U-676, U-679 offers improved hydrolysis resistance and aging resistance, supporting long-term bonding durability.

For heat-activated bonding, the recommended activation temperature is 130–140°C or higher to ensure full activation of the dried adhesive layer. The actual temperature depends on applied pressure, dwell time, and the substrates being bonded. Adding 2–5% water-dispersible polyisocyanate curing agent, such as SIWO EC-600, can significantly enhance high-temperature bonding performance.

U-679 also offers good compatibility with other waterborne resins, including slightly acidic resins and substances. Products stored for more than 12 months should only be used after passing relevant tests.

Frequently Asked Questions (FAQ)

+ 1. What Is SiwoPUD®-U-679?
+ 2. What Are the Main Advantages of U-679?
+ 3. What Materials Can U-679 Bond?
+ 4. What Bonding Methods Are Suitable for U-679?
+ 5. Is U-679 Suitable for Heat-Activated Bonding?
+ 6. What Is the Difference Between Polycarbonate-Based and Polyester-Based Urethane Adhesives?