Industry Standard Of "Knitted Thermal Underwear"

There are a wide variety of knitted products in China, and different varieties have different characteristics. The standard of "knitted thermal underwear and flakes" has standardized requirements for floral thermal underwear.

According to the characteristics of "knitted thermal underwear", 11 standards of internal quality are stipulated in the industry standard of knitted thermal underwear, including heat preservation rate, dry weight per square meter, air permeability, moisture permeability, pilling, pellet breaking strength, washing size change rate, stretch elasticity, formaldehyde content, fiber content and color fastness.

Among them, the heat preservation rate, air permeability and moisture permeability rate are important indicators to reflect the comfort of thermal underwear.

At present, the knitted thermal underwear has a large proportion in the market. The product's structure is the middle layer is the thermal insulation layer made of flakes and is the fastest developing type.

Intermediate flakes can be made of synthetic fiber composite fiber, polyester polypropylene staple fiber, functional fiber, silk, wool and so on.

The fabric structure is usually knitted single side structure, and fiber materials are generally made of pure cotton, polyester cotton blended fabric, modified polypropylene fiber and so on.

According to the experts' argumentation, a comfortable underwear is the result of the best match of 3 indicators, that is, the heat preservation rate is over 50%, the air permeability is controlled between 300 and 600mm/s, and the moisture permeability is more than 3000g/m2 / day.

Under static conditions, the more air in the fiber layer, the better the adiabatic performance. Once the air flows, that is, in the dynamic state, the thermal insulation property of the fiber layer will be greatly reduced.

Therefore, the middle wind resistance is extremely important.

The thermal conductivity of the water is 27 times that of the air, and the humidity of the air in the fiber layer increases. It makes people feel uncomfortable and wet. Therefore, the middle layer not only has better wind resistance, but also has a moisture conducting function.

Taking into account the above factors, the requirements for first grade in the standard are: the holding rate is more than 45%, and the air permeability (mm/s) is greater than 180, < 250; > 500, or less than 1000 two, the moisture permeability (g / m2.d) is greater than 3000.

The thermal underwear with the above 3 indexes is comfortable to wear.

(Jia Xiao)

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