What Is a Polyester Screen?

A polyester screen is a woven mesh screen cloth made from polyethylene terephthalate (PET) monofilament yarn, used in vibratory screeners for metal-free screening requiring superior chemical resistance, dimensional stability, and minimal moisture absorption. Polyester mesh is the second most common synthetic screen material after nylon, and it is the preferred non-metallic choice for wet screening, humid environments, and applications involving mild acids or solvents where nylon's moisture absorption would compromise aperture accuracy.

Polyester monofilament mesh is woven from precision-extruded PET yarn with controlled diameter and uniform tension to produce consistent aperture sizes from approximately 10 mesh to 500 mesh. PET's near-zero moisture absorption (less than 0.4%) gives polyester mesh exceptional dimensional stability — the apertures maintain their specified size regardless of humidity or wet/dry cycling. This property is particularly important in pharmaceutical and food screening where aperture consistency directly affects product quality and regulatory compliance. Polyester screens are compatible with standard screen frames for Sweco, Kason, Midwestern Industries, ScreenerKing, and other vibratory separators.

Polyester Screen Properties

Why This Matters in Vibratory Screening

Polyester screen is the go-to synthetic mesh when dimensional stability and chemical resistance are more important than the flexibility and abrasion resistance that nylon offers.

• Dimensional stability — Polyester's near-zero moisture absorption means the mesh openings remain at their specified size in wet screening, humid environments, and through wash-down cleaning cycles. Nylon screens in the same conditions may swell by several percent, effectively changing the cut point and producing off-spec product.
• Acid resistance — Polyester withstands most dilute mineral acids and organic acids that would degrade nylon. This makes it suitable for screening acidic food products (fruit juices, vinegar-based ingredients), chemical intermediates, and battery materials.
• Pharmaceutical compliance — PET mesh meets USP Class VI biocompatibility requirements and FDA 21 CFR 177.1630 for food and drug contact. Its dimensional stability ensures consistent aperture accuracy between cleaning cycles, which is essential for GMP pharmaceutical screening operations.
• Limitations — Polyester is attacked by strong alkalis (NaOH, KOH at elevated concentrations and temperatures), limiting its use in caustic environments. It has lower abrasion resistance than nylon and significantly lower tensile strength than stainless steel, resulting in shorter screen life under heavy loads or abrasive conditions.

Related Glossary Terms

• Nylon Screen — Polyamide mesh with better flexibility and anti-blinding properties
• Polypropylene Screen — PP mesh for strong acid resistance at lower cost
• PTFE Screen — Teflon-coated mesh for non-stick applications
• 304 Stainless Steel — Standard metallic screen material
• Screen Cloth — The filtering surface material in vibratory screeners

Polyester Screen FAQs

What is the difference between polyester and nylon screen for vibratory screening?

The key difference is moisture absorption. Polyester (PET) absorbs less than 0.4% moisture versus up to 8% for nylon, making polyester dimensionally stable in wet or humid environments where nylon mesh would swell and change its aperture sizes. Polyester also has better resistance to acids and UV light. Nylon offers better abrasion resistance and flexibility. Choose polyester for wet screening, humid environments, or acid-contact applications; choose nylon for dry screening where flexibility and anti-blinding are priorities.

Is polyester screen suitable for pharmaceutical screening?

Yes. Polyester (PET) mesh is widely used in pharmaceutical vibratory screening. It is FDA compliant (21 CFR 177.1630), meets USP Class VI biocompatibility requirements, and is compatible with most pharmaceutical cleaning and sterilization protocols. Its low moisture absorption ensures consistent aperture dimensions between cleaning cycles, which is critical for maintaining particle size specifications in GMP pharmaceutical manufacturing.