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TechnologIES – POROUS MEMBRANES

PTFE Hydrophobic Membranes

Durable and Versatile Hydrophobic Membranes with Superior Chemical Resistance

Sintered PTFE Hydrophobic Membrane Technology

Made from 100% pure PTFE that is free of PFOA, embark on a journey through the versatility of our Porex Virtek® PTFE membrane materials, which include expanded or sintered engineered manufacturing options to fulfill a diverse spectrum of venting demands. Standing out for their exceptional performance, our PTFE membranes offer unparalleled advantages across a multitude of applications

To address some of the most demanding medical and industrial applications, our PTFE membranes are capable of filtering particles as small as 0.1 micron in environments up to 500°F. This waterproof membrane is extremely durable and provides superior chemical resistance to aggressive media and corrosive solvents that can impact device functioning and overall performance.

Sintered PTFE Membrane

Expanded PTFE Membrane

Manufacturing process

Sintered PTFE Membrane

Naturally Robust​

Crafted from pure PTFE through a unique sintering process honed over decades using a combination of heat and pressure to bond the materials together. The objective is not to melt or change the main properties of the material – but to create a customized porous material specific to the customer’s needs and applications.  the skived membrane film creates a robust porous depth filter  – making it the most robust barrier to liquids entering from within or from leaking outside.

Able to be converted into endless formats, as well as surface treatments and printing making it our toughest membrane for demanding environments.​

This image show the process of how sintered PTFE membranes are made.

Expanded PTFE (ePTFE) Membrane

Versatility Meets Excellence ​

Our widest range of airflow and environmental protection properties in venting and filtration. ​Created by extruding and stretching PTFE under controlled conditions. With an array of supporting base layers, it combines depth and surface filtration to ensure reliability alongside some of the highest airflow and leak-proof

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Intro to Sintered PTFE Membrane Technology

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Options for customizing PTFE membranes

Physical properties

When incorporating a PTFE membrane into your product, it’s critical to understand the physical properties impacting the materials and functionality of the part including:

Understanding typical material properties will guide you in selecting the right polymer for your device’s function and operating conditions.  The above characteristics can be highlighted or downplayed based on your specific product needs.  Below is a chart that shows the common materials with their physical properties; however, this is not an exhaustive list.

  • Air flow rate: the volume of air being delivered at a given pressure drop through a specific area. This is a critical measure for designing a venting membrane. One important thing to note – air flow rate will increase through the same vent as the pressure drop increases.
  • Water entry pressure (WEP): the amount of water pressure required to have water break through the membrane. This is a critical measure when designing a water-resistant venting or filtering membrane.
  • Operating temperature: the temperature range at which the part will be required to operate. For Porex Virtek PTFE membrane, this value is 260°C / 500°F continuous.
  • Other key characteristics: Porex Virtek PTFE membrane is an extremely versatile material that is used in numerous markets and applications. Other application-specific characteristics that may be required for your application can include filtration efficiency, moisture vapor transmission rate, Gurley number, % reflectivity, and dielectric properties.

Chemical properties

Porex Virtek PTFE waterproof membrane is one of the most chemically resistant materials available in the market. There are only a handful of fluorinated acids that are not chemically compatible with sintered PTFE membranes, so it is always your safest choice if unknown chemicals may be in contact with the component.

Chemicals

PTFE

Acids (non oxidizing)

Good

Bases

Good

Oil

Good

Aromatic Solvents

Good

Non-Polar Alphatic
Solvent

Good

Polar-Aprotic Solvents

Good

Polar-Protic Solvents

Good

Halogenated Solvent

Good

Oxidizing Agents

Good

Material options

Polytetrafluoroethylene (PTFE)
For applications in need of ultra-hydrophobicity, high-temperature tolerances, high chemical resistance, and excellent robustness, sintered and porous PTFE membrane technology is a perfect choice.

Using our wide range of customizable solutions, we work closely with your engineering team to define your specifications and select the best PTFE membrane for your application.

Additive options

Below are some common additives and treatments that expand the potential functionality of your porous PTFE membrane:

  • Oleophobic treatment
  • Polypropylene scrim support layer
  • Adhesive backing
  • Screen Printing

Geometric options

Porex Virtek PTFE material begins as a 330 mm wide format (between 0.1 and 3.0 mm thick) and can be cut into porous PTFE sheets and other format options such as:

  • Slit rolls (8 – 330 mm)
  • Die-cut discs and various shapes
  • Rotary-cut plugs and discs
  • Cut discs “in web”
  • Water jet cut shapes
  • Zoned adhesive disc and other shapes
  • Rods & molded or spiral tubes
  • Thermoformed shapes
  • Porous PTFE sheets

Our engineers can work with you to better understand your manufacturing process and determine which size, shape, and dimensions are the best fit for your application.

Assembly & converting options

Customizable assembly and converting options for sintered PTFE are endless. Some of the more common methodologies include:

  • Thermal & ultrasonic welding
  • Overmolding
  • Die-cutting
  • Press fit
  • Pressure-sensitive adhesive (PSA)

To potentially decrease your assembly time and complexity, our engineers can work with you to better understand how your final product or device will be made. In many cases, we can combine multiple parts into one that is custom engineered.

If you require secondary processing of sheet and film products to meet your product design challenges, Porex also offers a Preferred Converter Program that can serve smaller order quantities.

Standard Porex Virtek product offerings

Porex Virtek® PTFE– General Purpose Venting product range (hydrophobic)

Item Number IP Rating † WEP* mbar
(Typical)		 Typical Airflow
l/hr/cm² @70mbar		 Filtration Efficiency**
>99.99%		 Thickness
mm		 Max Operating
Temp °C		 Salt Fog$
PMV10 64,67 270 107 0.5µ 0.13 260 No Pen.
PMV10L*** 64,67 270 85 0.5µ 0.3 100 No Pen.
PMV15 64,67 370 75 0.4µ 0.18 260 No Pen.
PMV15T‡ 64,67 370 75 0.4µ 0.18 260 No Pen.
PMV20 64,65,68 520 25 0.1µ 0.25 260 No Pen.
PMV25 65,67,68 765 17 0.2µ 0.1 No Pen.
PMV27 65,66,67,68 1050 7 0.1µ 0.19 260 No Pen.
† IEC std. 60529; IP 68 is a user defined and results must be verified by the user
*WEP = Water Entry Pressure
** According to IEST RP-CC007.2 2009
$ASTM B117-11 test method
***Laminated polyolefin mesh backing
<sup>‡ Oleophobic, AATCC TM 118 – Grade 8
Moisture Vapor Transmission Rate approx. 900g/m2/day. ASTM E96-16 water escaped from sealed cup @ 23±2°C, 50±10%rH chamber.
Properties are typical and not meant for specifications. Selected options and adhesives may affect properties
RoHS, WEEE, REACH Compliant (PFOA Free)

Porex Virtek® PTFE – Automotive / Oleophobic product range (hydrophobic & oleophobic)

Item Number IP Rating † WEP* mbar
(Typical)		 Typical Airflow
l/hr/cm² @70mbar		 Filtration Efficiency**
>99.99%		 Thickness
mm		 Max Operating
Temp °C		 Salt Fog$
PMA10‡ 64,67 370 75 0.4 µ 0.18 260 No pen.
PMA15‡ 65,67,68 520 25 0.1 µ 0.25 260 No pen.
PMA20‡ 65,66,67,68 1050 7 0.1 µ 0.19 260 No pen
† IEC std. 60529; IP 68 is a user defined and results must be verified by the user
*WEP = Water Entry Pressure
** According to IEST RP-CC007.2 2009
$ASTM B117-11 test method
***Laminated polyolefin mesh backing
‡ Oleophobic, AATCC TM 118 – Grade 8
Moisture Vapor Transmission Rate approx. 900g/m2/day. ASTM E96-16 water escaped from sealed cup @ 23±2°C, 50±10%rH chamber.
Properties are typical and not meant for specifications. Selected options and adhesives may affect properties
RoHS, WEEE, REACH Compliant (PFOA Free)

Porex Virtek® PTFE Medical-Grade membrane portfolio

Product Range Pore Size Range [µm]* Airflow Range (min)
l/h/cm² @ 70mbar		 Water Entry Pressure (min) mbar Material Thickness Range mm Filter Type Supporting Material
Porex Virtek® PTFE Sintered Hydrophobic Membranes 0.1 – 0.5** 0.25 – 70 10 – 800 0.1 – 3.0 Depth No support required
Porex Virtek® PTFE Sintered Oleophobic Membranes 0.1 – 0.5** 0.25 – 70 10 – 800 0.1 – 3.0 Depth No support required
Porex Virtek(R) PTFE Expanded Hydrophobic Membranes 0.1 – 0.5 12 – 312 50 – 5000 0.14 – 0.22 Surface PP/PET Lamination
* Typical values
** Dry Filtration Efficiency >99.99% in accordance with IEST RP-CC007.2 2009

Common applications for PTFE hydrophobic membranes

This list of application examples is just a small selection of what is possible. Check out our Areas of Expertise to explore a specific application.

Venting solutions

Vent

This is the most common functionality of Porex Virtek PTFE. From electrical enclosures, container venting, and diagnostics to medical devices and EV battery vents, many applications rely on venting for their product to work properly. Our durable and reliable PTFE vents are a perfect option to support your needs.

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Reflect

For UVC disinfection devices where a highly reflective and evenly distributed UVC energy is critical to ensuring proper deactivation of pathogens, our sintered PTFE membrane is an excellent choice.

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Filtration solutions

Filter

When addressing challenges involving cross-contamination, many devices must function as a filter and vent. Our sterilization container filters, which are reusable, are a prime example, as a vent allows pressure equalization during sterilization, and a filter provides a barrier to bacteria during subsequent storage. 

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Porous Laboratory Components

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Porosity Analysis on Hydrophobic Microporous Membranes

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Porex Virtek PTFE Fact Sheet

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