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 Ready Plastics 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
Request a Quote →More related guides
Applications
Industries
Compare to other materials
Frequently asked questions — Noryl FAQ