How does waterproof and breathable fabric achieve moisture permeability

Update:07-05-2021
Summary:

Waterproof breathable outdoor fabrics is a new type of […]

Waterproof breathable outdoor fabrics is a new type of textile fabric, its composition is composed of polymer waterproof and breathable material (PTFE membrane) and cloth. According to the needs of different products, it is made of two-layer composite and three-layer composite. It is widely used in outdoor clothing, mountaineering clothing, windbreakers, raincoats, shoes, hats and gloves, cold jackets, sporting goods, medical equipment, etc., and is gradually applied to fashion clothing.

 

The main functions of waterproof and breathable fabrics are: waterproof, breathable, breathable, insulating, and warm. Its moisture permeability is 16000g per square meter per 24 hours, the waterproof pressure can reach 8000-20000mm water column, and the insulation can reach up to 100,000 volts. The fabric can maintain its best effect in harsh environments, and can adapt to temperatures from 427 degrees to minus 200 degrees. In terms of production technology, the technical requirements for waterproof and breathable fabrics are much higher than those of ordinary waterproof fabrics; at the same time, in terms of quality, waterproof and breathable fabrics also have functional characteristics that other waterproof fabrics do not have. The waterproof and breathable fabric strengthens the air-tightness and water-tightness of the fabric. At the same time, its unique vapor permeability can quickly discharge water vapor inside the structure, avoid mold breeding in the structure, and keep the human body always dry, which perfectly solves the problem of ventilation, windproof, and waterproof. Warmth and other issues, it is a new type of healthy and environmentally friendly fabric.

 

Specifically, the waterproof and moisture-permeable fabric means that water does not penetrate the fabric under a certain pressure, but the sweat emitted by the human body can be transmitted to the outside through the fabric in the form of water vapor, so as to prevent the accumulation of sweat from condensing between the body surface and the fabric. It is a high-tech, unique and functional fabric to maintain the comfort of clothing. Waterproofing is not a problem for ordinary fabric workers, the key is how to achieve moisture permeability. Below, let's take a closer look at the types of waterproof and moisture-permeable fabrics.

 

One, through fiber to achieve moisture permeability
1. Ventair fabric. The earliest waterproof and moisture-permeable fabric is the famous Ventile fabric. It was designed by the British Shirley Research Institute in the 1940s. It uses 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 protection of British Air Force pilots during World War II. Anti-immersion suit. When the fabric is dry, the gap between the warp and weft yarns is relatively large, about 10 microns, which can provide a highly moisture-permeable structure; when rain or water drenches the fabric, the cotton yarn expands, reducing the gap between the yarns to 3 to 4 microns , This closed-cell mechanism is combined with a special water-repellent finishing to ensure that the fabric will not be further penetrated by rain. At present, this type of fabric has long been replaced by other waterproof and moisture-permeable fabrics.

 

2. Coolmax fabrics. International companies such as DuPont, Toray, etc. have researched the way of creating pores inside the fiber to drain sweat out of the body, which is the moisture wicking fabric on the market. This type of fiber production technology is concentrated in the hands of such large international companies, and the price is relatively high, making it difficult to become the mainstream of the market.

 

Second, through the coating to achieve moisture permeability
Using dry direct coating, transfer coating, foam coating, phase inversion or wet coating (solidified coating) and other process technologies, various coating agents with waterproof and moisture permeable functions are applied to the fabric On the surface of the fabric, the pores on the surface of the fabric are closed or reduced to a certain extent by the coating agent, thereby obtaining water resistance. The moisture permeability of the fabric is through the microporous structure formed on the coating by a special method or the hydrophilic group in the coating agent interacts with water molecules. With the help of hydrogen bonds and other intermolecular forces, the water molecules are adsorbed on the high humidity side. It is obtained by transferring to the analysis function of the low temperature side. The price of coated fabrics is low, and a certain degree of moisture permeability is realized, and they are widely used. However, due to its poor waterproof and moisture permeability and unsatisfactory feel, the market share is gradually decreasing.

 

The wet transfer coating fabric developed now makes the coated fabric radiate a new machine. It not only has high physical properties such as waterproof and moisture permeability, but also the surface cloth can be treated with 100% Teflon, and the washing fastness can reach 25 times. Above, the hand feel is also very good.

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