Polyurethane adhesives are a type of very important and high-performance polymer bonding materials. Their advantages are mainly reflected in the following aspects:
1. Excellent bonding performance and wide applicability
The most prominent advantage of polyurethane adhesives is that they have excellent bonding strength for a variety of materials and can be called "all-purpose adhesives". It can not only effectively bond hard materials with high polarity such as metal, glass and stone, but also bond materials with low surface energy or porosity such as plastic, rubber, wood, leather, fabric and ceramics with excellent performance. Especially for the "heterogeneous bonding" between materials of different properties, polyurethane adhesives can play an irreplaceable role and solve many bonding problems in engineering fields.
2. Excellent flexibility and impact resistance
The polyurethane molecular chain is composed of soft segments and hard segments. This special microphase separation structure endows its cured product with extremely high elasticity and toughness. Its adhesive layer not only has adjustable hardness, but also can withstand repeated bending, deformation and severe impact and vibration without brittle cracking or peeling. This feature makes it highly suitable for dynamic bonding applications, such as automotive structures, shoe soles, conveyor belts and other components that require fatigue resistance and shock absorption.
3. Excellent low-temperature resistance
Unlike many adhesives that become brittle and ineffective at low temperatures (such as epoxy resins), polyurethane adhesives can maintain good toughness at extremely low temperatures, and their glass transition temperature (Tg) can be very low. Therefore, it demonstrates unparalleled advantages in the manufacturing of refrigeration equipment, transportation vehicles and equipment in extremely cold regions.
4. Adjustable chemical and physical properties
By altering the raw material ratio and chemical structure, the performance of polyurethane adhesives, such as curing speed, hardness, modulus, and heat resistance, can be precisely designed, thereby meeting various application requirements ranging from soft elasticity to hard rigidity. Its product forms are also very diverse, including single-component, two-component, solvent-based, solvent-free, water-based and hot-melt types, etc., providing users with a wide range of choices.
5. Good chemical resistance and durability
The cured
Polyurethane Adhesive layer has excellent resistance to oils, ozone, oxygen and many chemical solvents. Although its high-temperature hydrolysis resistance is relatively weak, through formula optimization, its overall weather resistance and durability remain excellent, ensuring the long-term stability of the bonded structure.
In conclusion, polyurethane adhesives have become indispensable key materials in numerous fields such as industrial manufacturing, aerospace, automobiles, leather, construction, and packaging, thanks to their strong bonding universality, excellent toughness, superior low-temperature performance, high designability, and good durability.
