Fluoropolymers - FAQ

Solef® PVDF, Hylar® PVDF and Halar® ECTFE

Frequently Asked Questions

What does PVDF mean?

PVDF means polyvinylidene fluoride. It is the polymer obtained by polymerization of vinylidene fluoride (VDF or VF2): CH2=CF2.

What does ECTFE mean?

ECTFE stands for ethylene chlorotrifluoroethylene copolymer. It is an alternated copolymer obtained from the two monomers ethylene (CH2=CH2) and chlorotrifluoroethylene (CClF=CF2).

What is the maximum use temperature of PVDF and ECTFE?

Solef® PVDF or Halar® ECTFE offer a useful surface temperature range up to +150°C in non-load-bearing applications. The maximum service temperature can be affected by the presence of system stresses and chemical environment.

What is the difference between Solef® and Hylar® PVDF?

Hylar® is Solvay’s PVDF brand for the Coating market, while Solef® is Solvay’s  brand  known in applications like extrusion, molding, water purification membranes or lithium ion batteries.

What are the key differences among the different available Solef® PVDF grades?

Solef® PVDF grades can be mainly grouped in Homopolymers,  obtained from the polymerization only of vinylidene fluoride (VDF or VF2) , and Copolymers, where VDF is polymerized with other comonomers like hexafluoropropylene (HFP) or chlorotrifluoroethylene (CTFE).  In some cases a further functionalization or chemical modification is added to the mentioned polymeric backbone, introducing special properties for specific applications. In addition, different polymerization processes are used: emulsion polymerization and suspension polymerization. Grades having the same composition and polymerized according to the same process can still have different molecular weight, which determines a difference in its flow behavior when molten, as indicated by the melt flow index (MFI). Please ask your Solvay Specialty Polymers contact for guidance to choose the most suitable Solef® PVDF grade for your application.

Which is better – suspension PVDF or emulsion PVDF?

It depends on the final application. If properly processed, suspension PVDF has higher yield strength, better resistance to tensile creep and pressure. This advantage is important in applications where items are extruded, injection molded (piping systems, valves, fittings...) as well as water purification membranes processed by TIPS (temperature induced phase separation) process. Emulsion PVDF, on the other hand, is readily available as a fine powder ideal for dispersion coatings applications, and as a water-based latex.

Are Solef® PVDF and Halar® ECTFE processable by solution coating?

Solef® PVDF is soluble in some solvents. In general Solef® PVDF copolymers are more soluble than homopolymers. Halar® ECTFE, on the contrary, is not soluble in solvents at room temperature, but is readily processed by melting processing techniques. For more details and guidelines please ask your Solvay Specialty Polymers contact.

Do you have water-based PVDF grades?

Emulsion polymerization is used to produce PVDF latex, suitable for several different water-based applications ranging from waterborne coatings to manufacturing of lithium ion battery. Please ask your Solvay Specialty Polymers contact for more details.

What are the differences between Halar® ECTFE and ETFE?

ECTFE and ETFE are both partially fluorinated polymers. Their chemical difference resides in the chlorine atoms in ECTFE, which are substituted by a fluorine atom in the structure of ETFE. ECTFE and ETFE have similar chemical resistance, temperature rating, tensile properties, but ECTFE offers several advantages when compared to ETFE:
  • Higher tensile modulus
  • Harder surface
  • Better abrasion resistance
  • Superior fire resistance
  • Smoother surface
  • Better permeation resistance to water vapor and to gases such as oxygen, nitrogen, helium, carbon dioxide, chlorine, hydrogen chloride, hydrogen sulfide
 
Please ask your Solvay Specialty Polymers contact for guidance to choose the most suitable Halar® ECTFE grade for your application

What is better - Halar® ECTFE or fully fluorinated polymers like FEP or PFA?

No general answer can be given. When compared with fully fluorinated polymers like FEP or PFA, Halar® ECTFE offers much better permeation resistance to many chemicals. In corrosion protection applications like linings or coatings this is even more important than chemical resistance, as time to failure because of permeation (e.g. severe blistering or lining detachment) is often shorter than time for chemical attack. Please seek advice on your specific application from your Solvay Specialty Polymers contact.
 
In addition, Halar® ECTFE has much better mechanical properties, creep and pressure resistance at mild temperatures, which are key for piping systems or other items exposed to mechanical load. Last but not least, Halar® ECTFE has smoother surface, which helps limiting bacterial growth in water applications, and can be processed under much milder conditions than FEP or PFA.

Do you have a chart cross-referencing the different Solef® PVDF, Hylar® PVDF and Halar® ECTFE grades with grades from other manufacturers?

In many cases there are strong similarities between competing grades, in other ones there are differences that need to be analyzed in detail. Please seek advice on your specific application from your Solvay Specialty Polymers contact.

Can you tell me if Solef® PVDF or Halar® ECTFE is compatible with a certain chemical?

Solef® PVDF and Halar® ECTFE have excellent resistance to a wide range of chemicals. A discussion of the chemical resistance with data about a selection of chemicals is respectively available in the design guides for Solef® PVDF and Halar® ECTFE. For advice about other chemicals, please ask your Solvay Specialty Polymers contact. Our experts can provide opinions about the suitability of Solef® PVDF and Halar® ECTFE for particular chemical environments, based on our knowledge of the chemistry of PVDF and ECTFE on a constantly growing database of internal experimental results.

Are Solef® PVDF, Hylar® PVDF and Halar® ECTFE suitable for use in applications where they are exposed to ultraviolet (UV) light?

Solef® PVDF, Hylar® PVDF  and Halar® ECTFE have excellent intrinsic resistance to natural aging and do not require anti-UV additives to resist exposure to direct sunlight.  Their remarkable stability when exposed to solar radiation and weather is demonstrated by both accelerated and multiple-year outdoor weathering studies.

Do you have the properties required for a finite element stress analysis?

Yes, stress-strain curves and elevated temperature data are available for the most commonly used products. Please ask your Solvay Specialty Polymers contact for the data you need.

Do you have the material parameters required for conducting a flow simulation?

Yes, the material parameters have been developed for the most commonly used products. This includes PVT data which is needed for warpage analysis. Please ask your Solvay Specialty Polymers contact for the data you need.

What is the fire behavior of Solef® PVDF, Hylar® PVDF and Halar® ECTFE?

Solef® PVDF, Hylar® PVDF and Halar® ECTFE are self-extinguishing materials and offer superior fire resistance according to the various independent tests, such as UL-94, Limiting oxygen index (LOI) and auto-ignition temperature. Factory Mutual (FM) listed grades are available for both, Solef® PVDF and Halar® ECTFE.

Do I need special equipment for processing Solef® PVDF and Halar® ECTFE?

Solef® PVDF and Halar® ECTFE are melt-processable fluoropolymers that can be processed in the same way that conventional thermoplastics are processed. When processed by injection molding or extrusion, conventional three-zone single screw extruders can be employed, even if some peculiarities have to be taken into account. Processing recommendations are reported in the design guides respectively for Solef® PVDF and Halar® ECTFE.

Is it safe to process Solef® PVDF and Halar® ECTFE?

As with all polymeric materials exposed to high temperatures, good safety practice requires the use of adequate ventilation when processing Solef® PVDF and Halar® ECTFE to prevent exposure to irritating or toxic fumes and gases that may be generated in case of excessive heating. As a general reference about safety when processing Solef® PVDF and Halar® ECTFE products, please consult the “Guide to the Safe Handling of Fluoropolymer Resins” published by PlasticsEurope (Brussels, Belgium) or by the Society of the Plastics Industry (Washington, DC).

Is it necessary to dry Solef® PVDF and Halar® ECTFE prior to processing?

Drying is unnecessary since the resin will not absorb water. The low water absorption inhibits the dissipation of frictional static charges. Consequently, the resin container should be covered at all times to prevent the deposition of contaminants on the pellets or powder. When bringing the resin from a colder room, the closed drum liner should not be opened until the resin has reached the temperature of the processing room. This avoids condensing atmospheric moisture on the pellets or the powder.

Do you have any Solef® PVDF or Halar® ECTFE grades that are in compliance with food-contact (FDA, NSF 51, EU Regulation No. 10/2011 and its amendments) and/or drinking-water (NSF61, various national regulations in Europe) regulations?

Yes. Several grades of Solef® PVDF and Halar® ECTFE have been tested and comply with these regulations/standards. A general discussion on the regulatory status is found in the Solef® PVDF and Halar® ECTFE (hyperlinks) design guides. Information on the latest listings for specific grades is available from your Solvay Specialty Polymers contact.

Do Solef® PVDF or Halar® ECTFE products contain any of the substances governed by the European Union 2000/53/EC End-Of-Life Vehicles (ELV), 2011/65/EU and 2002/95/EC Restrictions on Hazardous Substances (RoHS), or 2002/96/EC Waste Electrical and Electronic Equipment (WEEE) Directives?

Yes. Solef® PVDF and Halar® ECTFE products meet the relevant requirements of these European Directives as related to the content of Cadmium or Cadmium compounds, lead, mercury and hexavalent Chromium Polybrominated Biphenyls (PBB) , Polybrominated Diphenylethers (PBDE)

Where can I find Safety Data Sheet of Solef® and Hylar® PVDF and Halar® ECTFE?

Please ask your Solvay Specialty Polymers contact for this type of document.

Where can I obtain Solef® and Halar® stock shapes for machining parts?

Please ask your Solvay Specialty Polymers contact.

Is it possible to pigment Solef® PVDF or Halar® ECTFE to make it a different color?

Yes, it is possible. Solef® PVDF-  and Halar® ECTFE –based masterbatches are readily available from major masterbatch suppliers like Colorant Chromatics, Clariant, Polyone, DainichiSeika, RTP and others. Should you need a resin matching a specific color rather than a color concentrate, please contact your Solvay Specialty Polymers contact.

Are antistatic grades of Solef® PVDF or Halar® ECTFE available?

Yes, they are available through the company A. Schulman

Are fiber-reinforced grades or other special compounds of Solef® PVDF or Halar® ECTFE available?

Yes, they are available through the company A. Schulman

What is your normal lead time and how do I place an order?

Please ask your Solvay Specialty Polymers contact.

Can I get a small sample of PVDF or ECTFE in powder, pellet, sheet, film or test specimen forms?

Please ask your Solvay Specialty Polymers contact.