FR-4 (Glass Epoxy Laminate) vs GFRP / GFK (Glass Fiber Reinforced Epoxy): 67% composition overlap. Moderate differences, generally not direct substitutes.
FR-4 (Glass Epoxy Laminate) vs GFRP / GFK (Glass Fiber Reinforced Epoxy)
Side-by-side chemical composition and mechanical property comparison.
Overview
FR-4 (Glass Epoxy Laminate)
Flame retardant woven fiberglass cloth with epoxy resin binder — the worldwide standard substrate material for printed circuit boards (PCBs). Designated NEMA grade FR-4 and IPC-4101. Good mechanical strength, dimensional stability and electrical insulation up to 130°C (Tg). Dielectric constant 4.2–4.7 at 1 MHz. Self-extinguishing (UL94 V-0). Used for single/multilayer PCBs, electrical insulation boards, structural composites in electronics, test fixtures and jigs. Available in thicknesses 0.1–50 mm.
GFRP / GFK (Glass Fiber Reinforced Epoxy)
Glass fiber reinforced epoxy composite — the cost-effective structural composite for industrial, marine and construction applications. E-glass fiber in epoxy matrix. Unidirectional: UTS ~1000 MPa, E ~40 GPa. Quasi-isotropic layup: UTS ~300 MPa, E ~18 GPa. Density 1.8–2.1 g/cm³. Electrically insulating (unlike CFRP). Used for boat hulls, wind turbine blades, chemical tanks/pipes, architectural panels, ladders, gratings, automotive body panels and electrical insulation structures.
| FR-4 (Glass Epoxy Laminate) | GFRP / GFK (Glass Fiber Reinforced Epoxy) | |
|---|---|---|
| Material Number | — | — |
| Category | Polymers | Polymers |
| Standard | IPC-4101 | ASTM D3039 |
Chemical composition (wt%) — Pro
| Element | FR-4 (Glass Epoxy Laminate) | GFRP / GFK (Glass Fiber Reinforced Epoxy) | Overlap |
|---|---|---|---|
| Epoxy Resin Matrix | 35–45% | 30–45% | OK |
| Glass Fiber (E-Glass) Cloth | 55–65% | — | — |
| Glass Fiber Reinforcement | — | 55–70% | — |
Mechanical properties — Pro
| Property | FR-4 (Glass Epoxy Laminate) | GFRP / GFK (Glass Fiber Reinforced Epoxy) | Unit |
|---|---|---|---|
| Flexural Strength | 380–480 | — | MPa |
| Tensile Strength | 280–340 | 900–1100 | MPa |
| Compressive Strength | 350–420 | — | MPa |
| Density | |||
| Glass Transition Temp (Tg) | |||
| Dielectric Constant (1MHz) | |||
| Dielectric Strength | |||
| UL94 Flammability | |||
| Water Absorption (24h) | |||
| Tensile Modulus | |||
| Fiber Volume Fraction |
Sign up free and get 3 full comparisons immediately.
Sign up free — 3 comparisons/day freeCompatibility Assessment
FR-4 (Glass Epoxy Laminate) and GFRP / GFK (Glass Fiber Reinforced Epoxy) have moderate differences (67% overlap). They are generally not direct substitutes. Consider the specific requirements of your application.
Automated assessment based on composition analysis
Frequently Asked Questions
Is FR-4 (Glass Epoxy Laminate) the same as GFRP / GFK (Glass Fiber Reinforced Epoxy)?
FR-4 (Glass Epoxy Laminate) and GFRP / GFK (Glass Fiber Reinforced Epoxy) have a 67% composition overlap. They are generally not directly interchangeable.
Can I replace FR-4 (Glass Epoxy Laminate) with GFRP / GFK (Glass Fiber Reinforced Epoxy)?
Generally not recommended. The compositions differ significantly (67% overlap). These materials have different alloying concepts and are intended for different applications.
What is the difference between FR-4 (Glass Epoxy Laminate) and GFRP / GFK (Glass Fiber Reinforced Epoxy)?
The main differences are in the following elements: overall alloying content. FR-4 (Glass Epoxy Laminate) is a Polymers grade, while GFRP / GFK (Glass Fiber Reinforced Epoxy) is a Polymers grade.
View full data for each material:
Data provided for reference only. Always verify against the applicable specification for critical applications.
All data is for reference only. Equivalents indicate similarity, not identity. Always verify against the applicable specification for safety-critical applications. materialref.com accepts no liability for decisions based on this data.