Fluoropolymers / Alfa Chemistry
Banner

Virgin PTFE

ONLINE INQUIRY

Due to its unique characteristics, PTFE is an ideal choice for performance. Figure 1 shows the various characteristics of PTFE.

The various properties and the role of PTFE performanceFigure 1. The various properties and the role of PTFE performance [1]

PTFE is mainly manufactured and supplied to the market in three forms, namely granular resin, fine powder and dispersion. Although they are both chemically high molecular weight polytetrafluoroethylene with extremely high melt viscosity, each requires different processing techniques.

Granular Resin

Granular PTFE resins are most commonly processed by compression molding and ram extrusion. The compression molding process of PTFE includes the following three important steps: (1) Preforming; (2) Sintering; (3) Cooling. Ram extrusion is a process for producing continuous lengths of PTFE extrudates. The pelletized resin used for ram extrusion must have good flow characteristics so that they can be easily fed into the extruder die tube.

Table 1. Typical Properties of PTFE Granular Resins

ResinBulk Density g/LSpecific GravityParticle Size, (average) μmTensile Strength, MPaElongation at Break, %Shrinkage, %Compression Ratio
Fine Cut250–5802.15–2.1720–3530–44300–4002.3–4.03.2:1 to 5.5:1
Free Flow480–9302.15–2.17220–65029–32290–3302.2 –2.82.2:1 to 2.5:1
Ram Extrusion575–6702.15–2.17600–80017–32290–4007.5–10.5
Modified400–8502.16–2.1720–3328–32400–6503.5-6.02.4:1

Fine Powder Resin

Fine powder resin is extremely sensitive to shearing, and the polymer after shearing cannot be processed. Therefore, they must be handled very carefully during transportation and processing. Generally, fine powder resins are processed in a "paste" form, which is prepared by mixing the powder with 15% to 25% hydrocarbon lubricants (such as kerosene, white oil, or naphtha).

PTFE Dispersions

Most fluoropolymers are produced by polymerization in an aqueous system, but in a subsequent step, the dispersion obtained during the polymerization process is coagulated into a solid form and converted into powder or granules. The aqueous dispersion of PTFE resin is a hydrophobic, negatively charged colloidal system that contains PTFE particles with a diameter of 0.05 to 0.5 μm suspended in water.

Applications

  • The PTFE resin produced is commonly used in electrical and electronic applications, mainly for the insulation of connecting wires in military and aerospace electronic equipment.
  • A large amount of PTFE is used as gaskets, seals, molded packing, bellows, hoses, and inner liners in fluid delivery systems in the chemical industry, and as linings for large storage tanks or process vessels. PTFE is also used in laboratory instruments.
  • Micropowders, PTFE homopolymers with a molecular weight significantly lower than ordinary PTFE, are commonly used as additives in many applications where they provide non-stick and sliding properties. They are added to plastics, inks, lubricants and paints.
  • Under the combined action of PTFE micropowders and modified TiO2, a hydrophobic composite coating with photocatalytic self-cleaning performance can be prepared, and the prepared material has sufficient hydrophobicity and effective self-cleaning effect.
  • The mechanism of surface modification of TiO2.Figure 2. The mechanism of surface modification of TiO2.

  • The impregnation of the fabric or the casting of the film can be easily accomplished using dispersions, suspensions or latex.

References

  1. E. Dhanumalayan, Girish M. Joshi, Adv Compos Hybrid Mater 1 (2018) 247–268.
  2. Yi Zhou, Mengyao Li, Xian Zhong, Zhiping Zhun, Pan Deng, HaiLiu, Ceramics International 41 (2015) 5341-5347.
Get in touch with us

If you have any services of interest, you are welcome to contact us to discuss the solutions that best suit your requirements.

※ Please kindly note that our services are for research use only.