Filter Seals
One Component. Two Functions.
A filter seal is a molded component that handles sealing and filtration at the same interface. The elastomeric body compresses against the mating surface to prevent leakage; the filter media integrated into that body controls what passes through. One part replaces what would otherwise require a seal, a separate filter element, and the hardware to hold them together.
Moldtech produces custom filter seals to your exact geometry, compound, and filtration specification all in-house at our 50,000 sq. ft. facility in Lancaster, NY.
Why Use a Filter Seal
- Single-component solution: sealing and filtration handled by one molded part
- Lower part count: fewer components to source, stock, and install
- Fewer leak points: no secondary retainer or interface between seal and filter element
- Fully custom: elastomer, filter media, geometry, and pore size specified to your application
- AS568 compatible: available in standard O-ring dimensions for drop-in prototype development
Elastomer Materials
Compound selection is driven by the operating environment: temperature range, chemical exposure, compression set requirements, and any applicable regulatory standards.
| Elastomer | Temp Range | Key Properties | Common Applications |
| Nitrile (NBR / Buna-N) | -40°F to +250°F | Oil and petroleum resistance | Hydraulic, fuel systems |
| Fluorocarbon (FKM / Viton) | -20°F to +400°F | Broad fuel, oil, and chemical resistance | Automotive, aerospace, industrial |
| Silicone (VMQ) | -65°F to +400°F | Biocompatible; FDA-compliant grades available | Medical devices, food processing |
| EPDM | -65°F to +300°F | Resistant to steam, water, and weathering | Fluid handling, HVAC, construction |
| Hydrogenated Nitrile (HNBR) | -40°F to +300°F | High mechanical strength; oil-resistant | Automotive, oil and gas |
| Chloroprene (CR / Neoprene) | -40°F to +250°F | Ozone and weather resistance | Marine, outdoor, general industrial |
| Fluorosilicone (FVMQ) | -85°F to +350°F | Fuel and solvent resistance at low temperatures | Aerospace fuel systems |
| Perfluoroelastomer (FFKM) | -20°F to +600°F | Widest chemical resistance of any elastomer | Semiconductor, chemical processing |
| Aflas (TFE/P) | -5°F to +400°F | Resistant to steam, acids, and bases | Oil and gas, chemical plants |
| Natural Rubber (NR) | -65°F to +180°F | High resilience and tear strength | General industrial, dynamic sealing |
Additional compounds available: Polyurethane (PU), Styrene Butadiene (SBR), Hypalon (CSM), Epichlorohydrin (ECH), Butyl (IIR), Santoprene (TPV), Polyacrylate (ACM), Polyisoprene (IR), Polybutadiene (BR).
For medical device and food processing applications, Moldtech produces silicone filter seals using LSR and HCR silicone molding in a cleanroom-controlled environment to meet FDA and USP Class VI requirements.
Filter Media
The filter media is co-molded directly into the elastomer body using Moldtech’s rubber injection molding and overmolding processes with no adhesives and no secondary assembly. Media selection is based on the process fluid, required filtration efficiency, operating temperature, and mechanical demands of the application.
| Property | Unit | Nylon | Polyester | Peak (PEEK) |
| Tensile Strength | psi | 55,000–97,000 | 65,000–108,000 | 47,000–108,000 |
| Elongation at Break | % | 20–35 | 15–30 | 20–40 |
| Working Temperature | °F | 239 | 302 | 482 |
| Abrasion Resistance | - | Good | Limited | Good |
| Acid Resistance | - | Good | Limited | Good |
| Alkaline Resistance | - | Good | Limited | Good |
| Stability in Solvents | - | Limited | Good | Good |
| Hydrolysis Resistance | - | Good | Limited | Good |
| Mesh Size Range | µm | 1–5,000 | 1–5,000 | 35–5,000 |
Additional Media Options
| Media | Key Properties | Best For |
| Stainless steel screen | Corrosion-resistant; high-temperature rated | Oil, fuel, hydraulic systems |
| Fabric weave | Flexible; adjustable weave density | Low-pressure, air, general use |
Pore size is specified per application, from sub-micron membranes up to 5,000 µm openings.
Understanding Open Area
Open area is the percentage of a mesh that allows flow through the filter. It directly affects flow rate, pressure drop, and filtration efficiency. Open area is calculated as:
Open Area (%) = c² × 100 / (c + b)²
Where c is the mesh opening size and b is the yarn diameter. Moldtech’s engineering team works with customers to specify the correct mesh geometry for the required balance between flow and particle capture.
Specialty Formulations
Available for applications with specific performance or regulatory requirements:
- Food grade
- Metal detectable
- Flame retardant
- Antistatic / ESD / RFI
- Electrically conductive
- Thermally conductive
- Internally lubricated
- High / ultra strength
- Fabric-reinforced
Design Considerations
Filter seals can be produced in virtually any cross-sectional profile or planform geometry including O-ring profiles, flat gaskets with mesh windows, port plugs with ID or OD screens, and custom overmolded frame configurations.
Selecting the right media and compound combination requires evaluating the following:
- Filtration requirements and target particle size
- Chemical compatibility between process fluid, elastomer, and media
- Corrosion resistance requirements
- Burst strength and flexibility under operating pressure
- Thermal stability of the media during molding and in service
- Regulatory compliance (FDA, automotive, MIL-spec)
Final part geometry is optimized around operating pressure differential, flow rate, temperature range, and mechanical stress and fatigue resistance across the service life of the component.
Sealing and Filtration Capabilities
Sealing
- Conformable profile for consistent surface contact and leak prevention
- Durometer and compression set tailored to the gland and application load
- Compound selected for compatibility with the process fluid or environment
Filtration
- Particle capture from macroparticulates down to molecular-level filtration
- Pore size and distribution set per application
- Filtration efficiency matched to the selected mesh or membrane
Get a Quote for Custom Filter Seals
Filter seals are engineered to order. Contact Moldtech’s team to define the compound, filter media, geometry, and tolerance requirements for your application.