FR-4 (Glass Epoxy Laminate) vs Silicone Rubber (VMQ/HTV): 0% composition overlap. Significantly different materials serving different application areas.
FR-4 (Glass Epoxy Laminate) vs Silicone Rubber (VMQ/HTV)
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.
Silicone Rubber (VMQ/HTV)
Silicone rubber (VMQ = Vinyl Methyl Polysiloxane) — THE extreme-temperature elastomer. Usable from -60°C to +230°C continuous (short-term +300°C). Excellent UV/ozone/weathering resistance. Biocompatible (FDA, USP Class VI). Low compression set. Electrically insulating. Lower tensile/tear strength than organic rubbers. Used for seals/gaskets, medical tubing/implants, food-grade components, baby products, automotive ignition boots, and LED/lighting encapsulation.
| FR-4 (Glass Epoxy Laminate) | Silicone Rubber (VMQ/HTV) | |
|---|---|---|
| Material Number | — | — |
| Category | Polymers | Polymers |
| Standard | IPC-4101 | ISO 37 |
Mechanical properties
| Property | FR-4 (Glass Epoxy Laminate) | Silicone Rubber (VMQ/HTV) | Unit |
|---|---|---|---|
| Flexural Strength | 380–480 | — | MPa |
| Tensile Strength | 280–340 | — | MPa |
| Compressive Strength | 350–420 | — | MPa |
Compatibility Assessment
FR-4 (Glass Epoxy Laminate) and Silicone Rubber (VMQ/HTV) 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 Silicone Rubber (VMQ/HTV)?
FR-4 (Glass Epoxy Laminate) and Silicone Rubber (VMQ/HTV) have a 0% composition overlap. They are generally not directly interchangeable.
Can I replace FR-4 (Glass Epoxy Laminate) with Silicone Rubber (VMQ/HTV)?
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 Silicone Rubber (VMQ/HTV)?
The main differences are in the following elements: overall alloying content. FR-4 (Glass Epoxy Laminate) is a Polymers grade, while Silicone Rubber (VMQ/HTV) 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.