Noryl Grades — EN265, GFN3 & 731 Compared
Three Noryl grades account for the majority of stock-shape rod, sheet, and tube: EN265 (the electrical-grade V-0 workhorse), GFN3 (30% glass-fiber reinforced for structural + electrical applications), and 731 (general purpose unfilled). Each targets a distinct application profile. Selecting the wrong grade — particularly using 731 where EN265's V-0 rating is required — is the most common Noryl specification error.
At a glance:
- EN265: UL 94 V-0 without halogen; the default electrical-grade stock shape; natural tan/gray
- GFN3: V-0 + 30% glass fiber; highest stiffness and HDT; black; for structural electrical parts
- 731: unfilled, general purpose; V-1 or HB flame; lower cost; for non-critical flame environments
- All grades share Noryl's core advantage: very low dielectric constant (2.65) and minimal moisture absorption
- EN265 dominates the stock-shape market; confirm grade availability for GFN3 and 731
Noryl EN265 — Electrical Grade, UL 94 V-0
What It Is
EN265 is the primary stock-shape Noryl grade and the most widely specified for electrical and electronic applications. It is an unfilled modified PPO+PS blend formulated with a non-halogen flame-retardant additive package to achieve UL 94 V-0 at a minimum wall thickness of 0.030" (0.75mm). V-0 is the highest UL 94 rating — the material self-extinguishes within 10 seconds after removal of the ignition source with no burning drips.
Properties of EN265
When to Specify EN265
EN265 is the correct choice when:
- UL 94 V-0 flame rating is required (electrical apparatus, IT equipment, telecom housings)
- Low dielectric constant and dissipation factor are required (RF applications, transformer bobbins)
- Dimensional stability in humid environments is critical
- IEC 60950-1 / IEC 62368-1 (or successor) compliance for IT equipment safety is required
EN265 is available from FedMat as rod, sheet, and tube. It is the default assumption when "Noryl" is specified for electrical applications without a grade designation.
Noryl GFN3 — 30% Glass-Fiber Reinforced, UL 94 V-0
What It Is
GFN3 adds 30% short glass fiber to the Noryl base resin. The fiber reinforcement significantly increases stiffness (flexural modulus from ~350,000 psi to ~900,000 psi), tensile strength (~12,000 psi vs 8,700 psi for EN265), and HDT (285°F vs 215°F). The V-0 flame rating is maintained. Color is black, due to the carbon-containing flame retardant and glass fiber dispersion.
Properties of GFN3
When to Specify GFN3
- Structural electrical parts requiring higher stiffness than unfilled EN265 (structural housings, load-bearing electrical enclosures)
- Higher-temperature service above 200°F and up to ~220°F continuous where EN265 is marginal
- Creep-critical applications under sustained load — glass fiber reduces creep significantly vs unfilled grades
- Precision machined parts where dimensional change from creep under clamp load would affect fit
Trade-offs vs EN265:
- Lower impact strength (GFN3 is brittle; elongation drops to 3–5%) — not suitable for shock-loaded applications
- Glass fiber increases tool wear — carbide tooling required; shorter insert life
- CTE anisotropy (lower in flow direction than transverse) — must account for in thermal cycling assemblies
- Slightly higher dielectric constant (~2.8 vs 2.65)
Noryl 731 — General Purpose Unfilled
What It Is
Noryl 731 is an earlier unfilled modified PPO+PS grade without the EN265 flame-retardant additive package. It carries a V-1 or HB flame rating (depending on thickness) — not V-0. Its mechanical properties are comparable to EN265 (tensile strength ~8,500 psi, flexural modulus ~340,000 psi), and it retains the same low dielectric constant and moisture absorption.
When to Specify 731
- Applications requiring Noryl's electrical and dimensional stability properties but where V-0 flame rating is NOT required
- Lower cost than EN265 — suitable for non-regulated environments
- Applications where halogen-free V-0 is irrelevant (indoor, non-electrical)
Do not specify 731 when the application requires UL 94 V-0 for electrical safety. This is the most common Noryl grade specification error: using 731 (which doesn't achieve V-0) where EN265 is required by the electrical safety standard.
Grade Selection Decision Guide
Order Noryl EN265, GFN3, or 731 in rod or sheet
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