Membrane filters allow the flow of fluids or gases while preventing the passage of particles and microorganisms. They are made of porous plastic films that retain particulates larger than a defined pore size. In other words, substances that are too large to fit through the filter’s pores are retained on the membrane’s surface and excluded from the purified stream.
Membrane filters are fabricated with precision die cutting, a manufacturing method that uses metal tools called dies to cut microporous plastics into precise shapes with specific geometries. Die cutting supports low-to-high volume quantities and is fast, accurate, and efficient. Engineers and designers can choose from various membrane materials that are strong, thermostable, and chemically and biologically clean.
Membrane Filter Materials
Material selection is a function of the type of fluid or gas to filter, membrane chemical compatibility, and maximum pore size. Uniformly thin membranes with high porosity provide the highest gas and fluid flow per unit area. Filter membranes with higher porosities also have more surface area for binding or adsorption, the adhesion of particulates from a gas, liquid, or dissolved solid to the membrane surface.
Types of membrane filter materials include polytetrafluoroethylene (PTFE), Porex® PTFE, cellulose acetate, nitrocellulose, and nylon. Compared to expanded PTFE (ePTFE), Porex® PTFE offers advantages in terms of production, performance, product range, and cost. Membrane filters are also die cut from polypropylene (PP), polyethersulfone (PES), polyvinylidene difluoride (PVDF), and glass fiber.
Membrane Filter Production and Use
Membrane filters can be manufactured using flatbed or rotary die cutting, high-speed punching, and kiss cutting. Plus, they can be supplied on rolls or sheets with or without an adhesive backing. Membrane filter diameters range from 0.25” to 60” with tolerances of 0.005″. Depending on the membrane material, pore sizes can range from 0.2 to 0.45 microns. Membrane thickness also varies.
Die cut membrane filters are used in food, beverage, medical, pharmaceutical, laboratory, and industrial applications. They’re also used in water purification. For example, membrane filters that are used in reverse osmosis (RO) remove minerals and other particulate matter from drinking water. Membrane filters are also used in microfiltration, nanofiltration, and ultrafiltration applications.
Learn More from Interstate
Interstate Specialty Products is a precision die cutter in Sutton, Massachusetts (USA) with ISO 9001:2015 and ISO 13485 certifications and a Class 100,000 (ISO 8) cleanroom. To learn how we can die cut membranes for your specific application, please contact us.
*Properties and applications shown throughout this website are typical. Your specific application should not be undertaken without independent study and evaluation for suitability.