FR-4 (Glass Epoxy Laminate) vs PBT (unfilled): 0% composition overlap. Significantly different materials serving different application areas.
FR-4 (Glass Epoxy Laminate) vs PBT (unfilled)
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.
PBT (unfilled)
Polybutylene Terephthalate — semi-crystalline polyester with fast crystallization (short cycle times), very low moisture absorption (0.15%), excellent dimensional stability, and good electrical properties. Key advantage over PA: properties nearly independent of humidity. Trade names include Ultradur (BASF), Celanex/Crastin (Celanese/DuPont), Valox (SABIC), Arnite T (DSM). Used for electrical connectors, relay housings, automotive sensors, and any precision part in humid environments.
| FR-4 (Glass Epoxy Laminate) | PBT (unfilled) | |
|---|---|---|
| Material Number | — | — |
| Category | Polymers | Polymers |
| Standard | IPC-4101 | ISO 10350 |
Mechanical properties
| Property | FR-4 (Glass Epoxy Laminate) | PBT (unfilled) | Unit |
|---|---|---|---|
| Flexural Strength | 380–480 | — | MPa |
| Tensile Strength | 280–340 | 55–60 | MPa |
| Compressive Strength | 350–420 | — | MPa |
Compatibility Assessment
FR-4 (Glass Epoxy Laminate) and PBT (unfilled) have significantly different compositions (0% overlap). These materials are not interchangeable and serve different application areas.
Automated assessment based on composition analysis
Frequently Asked Questions
Is FR-4 (Glass Epoxy Laminate) the same as PBT (unfilled)?
FR-4 (Glass Epoxy Laminate) and PBT (unfilled) have a 0% composition overlap. They are generally not directly interchangeable.
Can I replace FR-4 (Glass Epoxy Laminate) with PBT (unfilled)?
Generally not recommended. The compositions differ significantly (0% overlap). These materials have different alloying concepts and are intended for different applications.
What is the difference between FR-4 (Glass Epoxy Laminate) and PBT (unfilled)?
The main differences are in the following elements: overall alloying content. FR-4 (Glass Epoxy Laminate) is a Polymers grade, while PBT (unfilled) is a Polymers grade.
Related Comparisons
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.