Advantages of Polyurethane Adhesives:

    Due to the presence of strongly polar and chemically reactive isocyanate and urethane groups, polyurethane adhesives exhibit high reactivity, allowing them to cure at room temperature. As a result, they provide excellent chemical adhesion to a wide range of materials, including metals, rubber, glass, ceramics, plastics, wood, fabrics, leather, and more. These adhesives offer the following advantages:

High Reactivity: Polyurethane adhesives are highly reactive due to their isocyanate and urethane groups, enabling them to bond effectively with various materials.

Flexibility: They possess excellent flexibility, resulting in high peel strength, resistance to impact and vibration, and fatigue resistance.

Outstanding Low-Temperature Performance: Polyurethane adhesives excel in low-temperature environments, and their bond strength at low temperatures can be 2 to 3 times greater than at room temperature.

These characteristics make polyurethane adhesives an ideal choice for applications requiring strong, flexible, and low-temperature-resistant bonds.

Impact Resistance and Vibration Resistance: They are highly resistant to impact and vibrations, making them suitable for applications where durability is essential.

Fatigue Resistance: Polyurethane adhesives exhibit excellent fatigue resistance, ensuring long-term performance even under dynamic conditions.

Oil and Solvent Resistance: They are resistant to oils and solvents, maintaining their bond strength when exposed to these substances.

Ozone Resistance: These adhesives resist the damaging effects of ozone exposure, ensuring stability in outdoor applications.

Abrasion Resistance: Polyurethane adhesives withstand wear and abrasion, making them suitable for applications subject to mechanical stress.

Elasticity: They possess good elasticity, providing superior recovery after deformation and making them suitable for dynamic joint applications.

Excellent Electrical Insulation: Cured polyurethane materials exhibit strong electrical insulation properties, making them suitable for electrical applications.

Simple Processing: These adhesives offer straightforward processing, as they can cure at room temperature. Additionally, they can be heat-cured when required.

Disadvantages of Polyurethane Adhesives:

Sensitivity to Water: Polyurethane adhesives are sensitive to water, making them prone to bubble formation within the adhesive layer.

Limited Heat Resistance: They have relatively poor heat resistance, withstanding temperatures of typically up to only 150°C.

Toxicity: Polyurethane adhesives contain urethane groups (-NHCOO-), which have some level of toxicity. Caution should be exercised when using them.

Polyurethane rubber adhesive finds a wide range of applications and can be used for bonding various materials such as metal, rubber, plastic, fibers, wood, ceramics, glass, leather, either with each other or to themselves. It can also achieve some degree of bonding strength with challenging-to-bond plastics like polyethylene and polypropylene. However, its bonding strength for metals is not as high as that of modified epoxy, phenolic-nitrile, or phenolic-resorcinol-formaldehyde adhesives. Typically, it is primarily used for bonding soft materials, applications requiring resistance to impact, vibration, and low-temperature conditions. It is widely used in industries such as automotive, textiles, tapes, home appliances, electronics, footwear, packaging, and more.

Polyurethane rubber adhesive is typically a two-component system. The "A" component consists of polyesters, polyethers, or other polyhydroxy compounds with terminal hydroxyl groups, or modified with isocyanates to have terminal hydroxyl groups, while the "B" component comprises polyisocyanates or prepolymers capped with isocyanate groups, which can be modified with hydroxy compounds (polyesters, polyethers). These components are mixed in specific proportions for use, and depending on the types and properties of the "A" and "B" components, the adhesive can cure at room temperature or with the application of heat. To achieve a thermosetting cross-linked structure, at least one of the "A" or "B" components should contain compounds with three or more functional groups.