Production process of Ptfe Vent Membrane - Wuxi Sinceriend New Material Technology Co., Ltd.

1.Raw material selection
The first step in the production of PTFE ventilation membrane is to select high-quality polytetrafluoroethylene (PTFE) resin particles. These particles need to be of high purity and uniform particle size to ensure the stable performance of the finished membrane. High-purity PTFE resin can give the membrane good chemical stability and hydrophobicity, and uniform particle size is conducive to subsequent processing and molding.
2.Preforming process
The selected PTFE resin particles are mixed with specific additives, stirred evenly, and then initially formed by compression or extrusion. During compression molding, the material is pressed into a specific shape of blank under high temperature and high pressure; extrusion molding uses an extruder to extrude the mixed material into a thin sheet or tubular semi-finished product, laying the foundation for subsequent stretching and film formation.
3.Biaxial stretching film formation
This is the core step. The preformed PTFE semi-finished product is placed in a stretching device and biaxially stretched at a specific temperature and rate. Transverse stretching gradually widens the semi-finished product with the help of a roller device, and longitudinal stretching stretches the material through a traction device. During the stretching process, the PTFE molecular chains are rearranged and oriented along the stretching direction to form a uniform and fine pore structure, giving the membrane good air permeability and filtration performance.
4.Post-processing process
The PTFE ventilation membrane after stretching needs to be post-processed. Heat setting is used to eliminate stress in the membrane, stabilize the pore structure, and improve dimensional stability. Then, surface treatment, such as plasma treatment, is performed to improve the hydrophilicity or adhesion of the membrane surface to meet the needs of different application scenarios. Finally, the finished membrane is strictly tested for quality to ensure that its air permeability, waterproofness, chemical stability and other indicators meet the standards before it can be packaged and shipped.