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, the adhesives are in the flow state before curing. The bonding process is the process that the glue soaks on the surface of the bonded parts, and then the coating line of the pneumatic transmission shaft solidifies. For bonding, wetting contact is the primary condition of bonding.

Some high crystallinity polymer materials have good chemical stability. Their swelling and dissolution are more difficult than those of non-crystalline polymer. When bonded with solvent-based adhesives, it is difficult to diffuse and intertwine the polymer molecular chains and to form a strong adhesion force.

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.