How Much Do You Know About PTFE Waterproof Breathable Membrane?

PTFE membrane is a microporous membrane made of PTFE as raw material, using a special process through calendering, extrusion, biaxial stretching and other methods. PTFE membranes can be divided into clothing membranes, air filtration membranes, and air purification membranes according to their uses. The PTFE membrane has a fibril-like microporous structure with a porosity of more than 85%, 1.4 billion micropores per square centimeter, and a pore size range of 0.02μm-15μm, usually used as high-efficiency breathable waterproof materials.

1. The waterproof and breathable permeability mechanism of porous PTFE membrane

Water-proof and breathable means that water does not invade the fabric under a certain pressure, but the sweat vapor emitted by the human body can diffuse through the fabric or be transmitted to the outside world, and does not accumulate and condense between the body surface and the fabric, and does not make the human body feel stuffy. The waterproof and breathable membrane depends on the structure of the membrane and the surface wettability. The structure of the membrane has the greatest impact on waterproof and moisture permeability. This membrane is laminated with the excellent properties of ordinary textile fabrics and high-tech microporous membrane products. The resulting PTFE laminated fabric has a variety of excellent properties, which is waterproof and breathable, windproof and warm, resistant to germs, anti-infrared, anti-ultraviolet, fine dust filtering and other functions, fully showing the characteristics of differentiation and functionality. It is the main development direction of waterproof and breathable materials. After a full range of tests, it is proved that in most harsh environments, PTFE laminated fabric can always maintain the best physiological state of the human body, and is known as the second skin of the human body. It can be widely used in military and police uniforms, all kinds of outdoor sportswear such as mountaineering, skiing, golf, casual wear, shoes, hats, gloves, medical protective clothing, chemical protective clothing, flame retardant and high temperature fire fighting clothing, sleeping bags, and tents.

2. Waterproofness of PTFE membrane

Waterproofness refers to the degree of resistance of the fabric to the relative penetration of liquids, and the performance of the fabric against rain or penetration pressure in water. The PTFE microporous membrane has countless micropores with a pore diameter of 0.1～0.5μm, which is much smaller than the diameter of light mist (20μm), and much larger than the diameter of water vapor (0.0004μm), so water vapor can penetrate, but water It cannot pass due to the resistance of surface tension. In order to improve the water-resistance, the fabric must be waterproof (water repellent). The porous PTFE membrane is one of the most effective waterproof membranes on the market.

3. Thermal performance of PTFE membrane

PTFE membrane has excellent moisture permeability, which can transmit the steam discharged from the human body to the outside of the microclimate in time, prevent water vapor from condensing into liquid water, and reduce the possibility of water conduction heat. Although the surface of the breathable insulation membrane is dense with a large number of micropores, the wind cannot penetrate, effectively preventing air convection. Tests show that in a strong wind of 25m/s, the thermal insulation effect of the PTFE laminated fabric is 30-40% higher than that of the traditional down jacket.