Needle Punched Felts
Filmedia® – Experts in Industrial Filtration Solutions
As a manufacturer of premium needle-felt filtration materials, Filmedia® leverages extensive industry experience and a team of technical experts to gain a deep understanding of filtration requirements across diverse operating conditions. We provide scientifically sound, practical, and reliable filtration solutions tailored to our customers’ specific applications. Our comprehensive technical support—encompassing material selection, product design, and process optimization—aims to enhance filtration efficiency, extend product service life, and reduce overall operating costs.
☑ High filtration efficiency (up to 99.9%+).
☑ Suitable for a wide range of temperatures and corrosive environments.
☑ Stable structure; resistant to breakage。
☑ Compatible with various functional post-treatments.
☑ Long service life; suitable for continuous operation.
What is Needle-punched Felt?
Needle-Punched Felt, also known as needle-punched nonwoven fabric, is an industrial filtration material produced through a mechanical needling process. Unlike traditional woven fabrics, needle-punched felt does not rely on a warp-and-weft structure; instead, it is formed through the mechanical entanglement of fibers, resulting in more uniform pore distribution and improved filtration performance. This technology uses thousands of barbed needles to repeatedly and rapidly penetrate a pre-formed fiber web. During this process, the barbs drag surface fibers through the web, causing fibers to interlock and entangle in a three-dimensional structure. As a result, a nonwoven filtration material with specific thickness, high porosity, and high mechanical strength is formed. Although needle-punched felt appears dense, the fibers within it are evenly distributed, and its porosity typically reaches as high as 70% to 80%.
Common Post-Treatments for Needle-Punched Felt
While raw needle-punched felt possesses filtration capabilities, it must undergo specific post-treatments or finishing processes to withstand harsh, demanding industrial filtration environments.
☑ Singeing
The felt surface is rapidly exposed to a natural gas flame to burn off loose surface fuzz, creating a smooth surface that facilitates easy cake release (dust cake discharge).
☑ Calendering
The filter media is compressed between high-temperature heated rollers to control thickness, optimize surface pore distribution, and improve initial filtration efficiency.
☑ Heat Setting
The felt is tensioned and passed through a high-temperature oven (at a temperature slightly higher than its intended working environment). This process relieves internal mechanical stresses within the fibers, ensuring excellent dimensional stability and minimizing thermal shrinkage when the filter bag operates in hot industrial gases.
☑ PTFE Membrane Lamination
A micro-porous polytetrafluoroethylene (PTFE) membrane is thermally bonded to the surface of the needle-punched felt. This transforms traditional “depth filtration” into “surface filtration,” delivering ultra-high filtration efficiency (capturing $PM2.5$ and smaller particles) and effortless cleaning.
☑ Impregnation
The filter media is dipped or coated with chemical agents such as PTFE suspension, silicone oil, or fluorocarbon resins. This imparts water and oil repellency (hydrophobic & oleophobic properties) and protects the fibers from acid/alkali hydrolysis.
☑ Anti-Static Treatment
Conductive fibers (e.g., stainless steel fibers, carbon fibers) are blended into the fiber matrix, or an anti-static coating is applied to the surface. This prevents static buildup in explosive dust environments (e.g., flour mills, pulverized coal injection).
Properties of Needle-Punched Felt
| Model | Material / Scrim | Weight (g/m²) | Air Permeability (cm³/cm²·s) | Thickness (mm) | Warp Tensile Strength (N/50mm) | Weft Tensile Strength (N/50mm) | Warp Elongation (%) | Weft Elongation (%) | Treatment | Continuous Temperature (°C) |
|---|---|---|---|---|---|---|---|---|---|---|
| 001UA | 100% Polyester | 500 ±5% | 15 ±25% | 1.8 ±0.2 | ≥1000 | ≥1200 | ≤30 | ≤55 | Heat Set, Singed & Calendered | ≤130 |
| 001FA | 100% Polyester | 500 ±5% | 15 ±25% | 1.8 ±0.2 | ≥1000 | ≥1200 | ≤30 | ≤55 | Water & Oil Repellent | ≤130 |
| 002UA | PET / Antistatic PET | 500 ±5% | 15 ±25% | 1.8 ±0.2 | ≥1000 | ≥1200 | ≤30 | ≤55 | Heat Set, Singed & Calendered | ≤130 |
| 003UA | PET + 5% Antistatic Fiber / PET | 500 ±5% | 15 ±25% | 1.8 ±0.2 | ≥1000 | ≥1200 | ≤30 | ≤55 | Heat Set, Singed & Calendered | ≤130 |
| 001UM | 100% Polyester | 500 ±5% | 4 ±25% | 1.8 ±0.2 | ≥1000 | ≥1200 | ≤30 | ≤55 | PTFE Membrane Laminated | ≤130 |
| 100UA | 100% Polypropylene | 500 ±5% | 11 ±25% | 1.8 ±0.2 | ≥1000 | ≥1200 | ≤30 | ≤55 | Calendered | ≤80 |
| 200UA | 100% Acrylic | 500 ±5% | 15 ±25% | 1.8 ±0.2 | ≥700 | ≥1100 | ≤55 | ≤50 | Heat Set, Singed & Calendered | ≤90 |
| 301KA | PPS | 500 ±5% | 10 ±25% | 1.8 ±0.2 | ≥800 | ≥1300 | ≤25 | ≤50 | PTFE Impregnated | ≤160 |
| 301KM | PPS | 500 ±5% | 4 ±25% | 1.8 ±0.2 | ≥800 | ≥1300 | ≤25 | ≤50 | PTFE Membrane Laminated | ≤160 |
| 303KA | PPS / PTFE | 580 ±5% | 10 ±25% | 1.8 ±0.2 | ≥700 | ≥1100 | ≤20 | ≤30 | PTFE Impregnated | ≤160 |
| 303KM | PPS / PTFE | 530 ±5% | 4 ±25% | 1.8 ±0.2 | ≥700 | ≥1100 | ≤20 | ≤30 | PTFE Membrane Laminated | ≤160 |
| 311KA | PPS + PTFE / PTFE | 650 ±5% | 10 ±25% | 2.0 ±0.2 | ≥800 | ≥1200 | ≤25 | ≤50 | PTFE Impregnated | ≤160 |
| 500HA | Nomex® / Nomex® | 550 ±5% | 21 ±25% | 2.1 ±0.2 | ≥800 | ≥1200 | ≤25 | ≤50 | Heat Set, Singed & Calendered | ≤200 |
| 500KA | Nomex® / Nomex® | 550 ±5% | 18 ±25% | 2.1 ±0.2 | ≥800 | ≥1200 | ≤25 | ≤50 | PTFE Impregnated | ≤200 |
| FMS 801B | Fiberglass Composite / Fiberglass | 900 ±5% | 20 ±25% | 2.1 ±0.2 | ≥2500 | ≥2500 | ≤10 | ≤10 | PTFE Impregnated | ≤240 |
| 600KM | PTFE / PTFE | 780 ±5% | 4 ±25% | 1.6 ±0.2 | ≥700 | ≥700 | ≤10 | ≤10 | PTFE Membrane Laminated | ≤240 |
Applications of Needle-Punched Felt in Filtration
Industrial Dust Filtration
Needle-punched felt is widely used in baghouse dust collection systems for industrial flue gas and particulate control, such as:
- Cement production and kiln exhaust gas treatment
- Steel metallurgy and foundry dust collection
- Coal powder conveying systems and coal-fired boilers
- Chemical dust and catalyst recovery
- Municipal waste incineration flue gas treatment
- Metal dust such as aluminum and magnesium (high explosion-risk environments)
Liquid Filtration Applications
Certain specialty needle-punched felts are also used in liquid filtration applications, including:
- Chemical solution filtration
- Pharmaceutical and food industry filtration
- Wastewater treatment and solid-liquid separation
- Electroplating and metalworking fluid filtration