Plastic bonding is a crucial processing technology for joining plastic materials such as thermoplastics and thermosets with each other, or plastic with dissimilar materials. Typical methods include chemical bonding using various adhesives such as solvent-based, epoxy-based, and acrylic-based types, and physical welding utilizing heat, such as ultrasonic welding, hot plate welding, and laser welding. The optimal method is selected by considering factors such as the type of plastic to be joined, surface condition, required strength, heat resistance, chemical resistance, and productivity. In particular, improving wettability through surface treatment significantly affects bonding strength. It is an indispensable technology for achieving weight reduction and complex shapes in a wide range of fields such as automotive parts, home appliances, medical devices, and electronic components.