Polypropylene (PP) Needle Punched Felt Filter Bag
Polypropylene needle punched felt filter bags from LYH fit chemical processing, electroplating, food handling, pharmaceutical powders, and humid or acidic dust collection. Buyers choose PP filter bags when they need superior acid and alkali resistance, excellent chemical stability, and reliable performance in wet or corrosive environments below 90 °C.
We supply polypropylene filter bags from China with custom size discussion, fabric weight options (400–600 GSM), and full surface treatment support. If your project requires a specific bag diameter, length, top/bottom construction, or chemical-compatibility match, we can review the RFQ and pair the right PP felt to your dust collector or process condition.
Key Technical Specifications
| Parameter | Value |
|---|---|
| Material | 100% Polypropylene (PP) staple fiber, scrim-supported needle felt |
| Continuous Operating Temperature (Dry) | 90 °C / 194 °F |
| Continuous Operating Temperature (Moist) | 94 °C / 201 °F |
| Maximum Short-Term Surge Temperature | 107 °C / 225 °F |
| Specific Density | 0.9 g/cm³ |
| Moisture Regain (20 °C, 65% RH) | 0.1% |
| Standard Fabric Weight | 400 / 450 / 500 / 550 / 600 GSM (customizable) |
| Air Permeability | 14–22 m³/m²/min @ 200 Pa |
| Tensile Strength (Warp / Weft) | ≥ 900 N / 5×20 cm |
| Filtration Efficiency | ≥ 99.9% (with PTFE membrane: ≥ 99.99%) |
Material Properties
Outstanding Acid & Alkali Resistance — Polypropylene exhibits exceptional resistance to most strong mineral acids, organic acids, and alkalis across the full pH range. It is one of the few filter media that withstands continuous exposure to caustic soda, hydrochloric acid, and sulfuric acid at moderate temperatures.
Excellent Hydrolysis Resistance — With near-zero moisture regain (0.1%) and full water-repellent behavior, PP felt is the preferred choice for wet, humid, or saturated gas streams where polyester would degrade.
Lightweight & Cost-Effective — At only 0.9 g/cm³ density, PP delivers more filtration area per kilogram than any other synthetic media, lowering material cost per bag.
Good Mechanical Strength — Strong tensile and abrasion resistance under normal operating conditions; suitable for pulse-jet cleaning at standard frequencies.
Limitations to Note — PP is not suitable above 90 °C continuous service. Under prolonged UV exposure or operation above 82 °C without mechanical support, PP will deform or elongate. PP is also subject to oxidation by strong oxidizing agents (concentrated nitric acid, peroxides, chlorine).
Available Surface Treatments
| Treatment | Function | Recommended For |
|---|---|---|
| Singeing (SIPP) | Removes loose surface fibers via flame; improves cake release | Standard dry / wet dust |
| Calendering / Glazing (GLPP) | Heated rollers densify the surface; enhances surface filtration and reduces blinding | Fine-particle capture, low pressure drop |
| Heat Setting | Stabilizes felt dimensions, eliminates shrinkage during operation | All applications |
| PTFE Membrane Lamination | Microporous ePTFE membrane on dust side; emissions ≤ 5 mg/Nm³ | Low-emission compliance, fine PM capture |
| Anti-Static | Conductive carbon fiber or stainless-steel filament; surface resistance 10³–10⁸ Ω·cm | Combustible / explosive dust |
| Water & Oil Repellent (WO) | Enhanced moisture and oil rejection finish | Sticky, oily, or saturated streams |
Bag Construction
- Top Constructions — Snap band, flange top, ring top, soft cuff, raw edge, strap top
- Bottom Constructions — Disc bottom, flat bottom, reinforced double-bottom, wear-strip bottom
- Sewing — 3-needle chain stitch with PP or PTFE thread (PP thread recommended for chemical compatibility); overlock or lockstitch on bottoms
- Reinforcement — Optional wear strips, custom skirts, double-bottom reinforcement for abrasive dust
Standard Sizes & Customization
| Dimension | Range |
|---|---|
| Diameter | Φ100 / 120 / 125 / 130 / 150 / 160 / 180 / 250 mm (or custom) |
| Length | 1,000 – 8,000 mm (custom lengths available) |
| Tolerance | Diameter ± 2 mm, Length ± 5 mm |
Non-standard sizes, special top/bottom configurations, and OEM patterns produced from your drawings or sample bag.
Industry Applications
- Chemical Processing — acid mist, alkali fume, chlor-alkali, fertilizer dust
- Electroplating & Surface Treatment — pickling line fume, plating bath ventilation
- Pharmaceutical Manufacturing — wet powder handling, ambient-temp granulation
- Food & Beverage — sugar refining, starch handling, food powder collection
- Mineral Slurry Filtration — wet ore processing, tailing dewatering
- Pigment & Dye Manufacturing — wet pigment dust, organic intermediate
- Battery & Electrolyte Production — corrosive aerosols, electrolyte mist
- Pulp & Paper — wet stock filtration, white-water recovery
- Wastewater & Sludge — humid effluent gas, low-temperature corrosive streams
- Cold-End Power Plant — economizer and ID fan zones with acidic condensate
Why Choose LYH Polypropylene Filter Bags
- Premium PP fiber sourced from leading producers; scrim-supported felt for stability and chemical durability
- Strict QC on fabric weight, air permeability, tensile strength, chemical resistance
- Full customization — any size, any top/bottom, any treatment combination
- Fast lead time — standard sizes ship in 10–20 days
- Engineering support — application engineers help match media to your gas chemistry, temperature, and emission target
- Reliable logistics — individually wrapped, ring-up packing, sea / air / courier shipment worldwide
FAQ
Q1: What is the maximum operating temperature of polypropylene filter bags? PP filter bags operate continuously at up to 90 °C (194 °F) dry / 94 °C moist, with short-term peaks up to 107 °C. For higher temperatures, choose polyester (135 °C), acrylic (135 °C), or PPS (190 °C).
Q2: Why choose polypropylene over polyester? PP has superior acid, alkali, and hydrolysis resistance, making it the preferred choice for wet, humid, or chemically aggressive streams. Polyester is preferred only when operating temperatures exceed 90 °C and the gas stream is dry.
Q3: Can polypropylene filter bags be used for liquid filtration? Yes — PP needle felt is widely used for liquid bag filtration in chemical, electroplating, and wastewater applications. Its near-zero moisture regain and broad chemical compatibility make it ideal for both gas and liquid duty.
Q4: Is polypropylene resistant to oxidizing chemicals? PP is not resistant to strong oxidizing agents such as concentrated nitric acid, hydrogen peroxide, or chlorine gas at elevated temperature. For these conditions, choose PTFE filter bags.
Q5: Can polypropylene filter bags be made anti-static or PTFE-coated? Yes. Anti-static PP (with carbon fiber or stainless-steel filament) is available for combustible powder applications. PTFE membrane lamination is available for ultra-low emission requirements.
Q6: What information do I need to provide for a quote? (1) bag dimensions, (2) top/bottom construction, (3) operating temperature & humidity, (4) gas chemistry (acid / alkali / oxidizer), (5) dust type & concentration, (6) emission requirement, (7) quantity. A drawing or sample bag is even better.
Our Partner
