Functional Materials :ETFE Film and PTFE Film

ETFE chemical name ethylene tetrafluoroethylene copolymer, is a fluorine-containing polymer thermoplastic material, is an artificial high strength fluoropolymer, the most advanced film material in the world.

PTFE chemical name polytetrafluoroethylene, is a chemical inert material, is based on glass fiber as a substrate to form PTFE film. PTFE also has excellent durability, easy cleaning and stability.

1. The characteristics of PTFE film

(1) The biggest feature of PTFE film is high strength, medium strength PTFE film thickness is only 0.8mm, but its tensile strength has reached the level of steel; Moreover, the elastic modulus is low, which is conducive to the formation of complex curved surface modeling.

(2) The use of a wide temperature range, can be used in the temperature range of -70℃ ~ 230℃.

(3) With unique optical properties, the incident light during the day becomes a natural warm light, preventing glare, no shadow, uniform distribution of light; Almost no ultraviolet light penetrates, preventing the fading of interior decorative materials and equipment; The high reflection performance at night makes the room have excellent lighting effect, reduce power consumption, and can bring out the brilliance of the building in the night sky.

(4) Good self-cleaning, rain can wash away the surface attachment.

(5) Has a high light transmittance, the light transmittance is 13%, the thermal reflectivity is 73%, and the heat absorption amount is very small;

(6) The service life is more than 25 years.

2.ETFE film characteristics

ETFE film has high tensile strength, impact strength and tear resistance. The thickness of ETFE film is usually 0.05 ~ 0.25mm. With the increase of thickness, the hardness of the film will increase, but also more brittle, increasing the difficulty of processing.

A typical use of ETFE materials is to "weld" two or three layers of film together and transport them to the site. Then air them up to inflate them into an air pillow.

(1) made of fluoroplastic, it can also apply pre-tension as the fabric film;

(2) Resistance to temperature changes, can be directly exposed to -200℃ -150 ℃ temperature;

(3) The transmittance of ETFE film can be as high as 95%. The material does not block the transmission of light such as ultraviolet rays to ensure the natural light inside the building. By surface printing, the semi-transparency of the material can be further reduced to 50%;

(4) The unique anti-adhesion surface makes it have the characteristics of high pollution resistance and easy cleaning, usually the rain can remove the main dirt;

(5) ETFE film reaches B1, DIN4102 fire rating standards, and will not drip when burning. The thickness is usually 0.05mm ~ 0.25mm, and the film is very light, only 0.15kg ~ 0.35kg per square meter. This feature makes it have considerable advantages even in the case of film melting caused by smoke and fire;

(6) The ETFE film is completely recyclable material, which can be reused to produce new membrane materials, or to produce other ETFE products after separating impurities;

(7) corrosion resistance, and at the same time has a strong adhesion characteristic of metal, to overcome the non-adhesion defect of polytetrafluoroethylene on metal, coupled with its average linear expansion coefficient close to the linear expansion coefficient of carbon steel, ETFE (F-40) become an ideal composite material and metal, with excellent negative pressure resistance characteristics;

(8) ETFE film has a service life of at least 25 to 35 years, which is an ideal material for permanent multi-layer movable roof structures;

(9) It is usually used in construction in the form of air cushion, and the economic span of air cushion is generally 3~5 m. Through steel structure, aluminum alloy structure or cable mesh, multiple air cushions can be connected together to form a large covering space. In terms of each air cushion, it is an inflatable structure; In terms of the whole structure, each air cushion unit is equivalent to the envelope structure. Constant monitoring and replenishment of air pressure is required.

In contrast, ETFE film has higher light transmittance and better chemical resistance than PTFE film, and can resist most acids and bases; ETFE film has strong resistance to natural aging and good machinability and mechanical properties, because ETFE film is directly made of plastic film, no substrate, so its tensile strength, tear strength is not as good as PTFE film, and one-time investment is high, high maintenance costs during use, poor resistance to sharp objects.