In recent two years, great breakthroughs have been made in die design, injection molding technology and coating performance. These new materials have excellent physical and mechanical strength, and are very light and resistant to chemical corrosion. However, the surface adhesion is poor and special surface treatment is needed.

Generally, adhesives are in a flow state before they are cured. The bonding process is a process in which the glue soaks on the surface of the bonded parts and then solidifies. For bonding, wetting contact is the first condition of bonding.

The swelling and dissolution of some high crystallinity polymer materials are more difficult than that of non-crystalline polymer materials. When bonded with solvent-based adhesives, it is difficult for polymer molecular chains to diffuse and intertwine, and the strong adhesion cannot be formed.

In addition to the structural reasons, some polymers are difficult to stick to because of the existence of weak boundary layers on the surface of materials. Polyolefin resin itself contains low molecular weight substances and additives (such as smoothing agent, antistatic agent, etc.) which are easy to precipitate, collect on the surface of the resin and form a weak interfacial layer with low strength. It shows poor adhesion and is not suitable for printing, compounding and bonding. Processing.