PU Air Filters Foaming Frame Molding and Sealing Integrated Process Technology

PU frame molding is the key molding process for high-end automotive air filters, determining the overall structural stability and sealing performance of the filter. The factory adopts advanced one-piece PU foaming molding technology, using high-elasticity and aging-resistant polyurethane raw materials, which are injected into customized precision molds through automatic proportioning equipment. The 3:1 standard PU adhesive ratio ensures excellent bonding strength and flexibility.

In the molding process, the pleated filter element is fixedly positioned in the mold, and the PU material fully wraps the edge of the filter paper after high-pressure foaming, forming an integrated seamless sealing frame. Compared with traditional glue bonding and rubber frame assembly, one-piece foaming avoids gaps, degumming, and air leakage risks at the connection. The PU frame has excellent shock resistance, high-temperature resistance, and low-temperature toughness, adapting to extreme temperature environments from minus 30 degrees to 120 degrees Celsius in the engine cabin.

After molding, constant-temperature curing treatment is carried out to stabilize the molecular structure of the PU material, enhance compression resilience and aging resistance. The integrated PU frame process greatly improves the overall durability and sealing performance of the air filter, effectively blocking unfiltered outside air from entering the engine.