1. Realize ventilation by laminating waterproof and breathable membrane
(1) PTFE film
The diameter of water vapor molecules is 0.0004 microns, the diameter of the smallest mist in rainwater is 20 microns, and the diameter of drizzle is as high as 400 microns. If a film with a pore diameter between water vapor and rainwater can be made, it can be both waterproof and Breathable. U.S. Gore Company used polytetrafluoroethylene (PTFE) to become the first company to produce the film, and after laminating it with fabric, it was named as GORE-TEX film. After continuous efforts, it becomes a composite film by laminating with other hydrophilic films. Special treatment on the film greatly improves its fastness. It is generally believed that the water pressure of the fabric can reach 10000mm, and the water pressure will decrease significantly after washing 6-7 times; the maximum air permeability can reach 10000g/sqm*24hrs, but it is not possible that the fabric just made can reach this value. After several washings, part of the glue is washed away, the available pores increase, and the air permeability increases; at the same time, the clothing made of this fabric can also block the intrusion of cold wind, preventing the wind from taking away the heat emitted by the body through the cloth, making the body not It feels cold due to the loss of heat; in addition, the fabric can resist 97.5% of ultraviolet rays.
(2) TPU film
TPU is short for Thermoplastic Polyurethane Film, which is a non-porous hydrophilic film. Since the film itself has no pores, the waterproof effect is naturally good. Ventilation is mainly achieved through its hydrophilic properties. Relying on the difference in vapor pressure inside and outside the clothes, the steam is transferred from high pressure to low pressure, thus realizing the function of ventilation.
3. Through fiber to achieve ventilation
(1) Ventair fabric.
It was designed by the British Shirley Research Institute in the 1940s. It used Egyptian long-staple cotton high-count, low-twist pure cotton yarn and high-density heavy-weight flat fabric. It was originally mainly used for cold-proof and anti-cold resistance of British Air Force pilots during World War II. Immersion. When the fabric is dry, the gap between the warp and weft yarns is relatively large, about 10 microns, which can provide a highly breathable structure; when the fabric is exposed to rain or water, the cotton yarn expands, reducing the gap between the yarns to 3 to 4 microns. A closed cell mechanism is combined with a special water-repellent finishing to ensure that the fabric is not further penetrated by rain. This type of fabric has long been replaced by other waterproof and breathable fabrics.
(2) Coolmax fabrics
Perspiration can be discharged from the body by creating holes in the fiber, which is the moisture wicking fabric currently on the market.