# Phenolic Laminated Sheet: The Classic Choice for Industrial Electrical Insulation
Introduction to Phenolic Laminated Sheet
Phenolic laminated sheet, also known as bakelite or phenolic cotton cloth laminated board, is a laminated insulation material made by impregnating cotton cloth with phenolic resin and then hot-pressing it. Historically one of the most widely used insulation materials in the electronic and electrical industry, it continues to play an irreplaceable role in many industrial applications today.
Dongguan Chaorong Electronics Co., Ltd. has long supplied phenolic sheet raw materials and provides cutting, drilling, milling groove and other precision machining services, with thickness range of 1–50mm and customizable dimensions.
Major Grades and Specifications
| Grade | Standard | Temperature Class | Key Features |
|---|---|---|---|
| Phenolic Cotton Cloth Board (PFCP) | IEC 60893 | E-class (120°C) | Balanced performance, low cost |
| Epoxy Glass Cloth Board (FR4/G10) | IEC 60893 | F-class (155°C) | High mechanical strength, moisture resistant |
| High-Strength Phenolic Cotton Board | — | E-class (120°C) | High impact resistance, high toughness |
Core Performance Parameters
| Performance | Typical Value | Test Standard |
|---|---|---|
| Dielectric Strength (perpendicular to lamination) | ≥15 MV/m | IEC 60243 |
| Dielectric Withstand Voltage (parallel to lamination) | ≥30 kV | IEC 60243 |
| Flexural Strength (lengthwise) | ≥100 MPa | IEC 60893 |
| Impact Strength (Izod) | ≥25 kJ/m² | ISO 180 |
| Water Absorption | ≤2.0% | IEC 60893 |
| Density | 1.30–1.45 g/cm³ | ISO 1183 |
| Insulation Resistance | ≥10⁸ Ω | IEC 60093 |
Typical Application Scenarios
1. Power Adapter Insulation Structures
Phenolic sheet is widely used in traditional power transformers and switching power supplies as insulation spacers, support strips, and partition boards. Its cost is only 1/3 to 1/2 that of FR4 fiberglass board, giving it a clear advantage in high-volume, cost-sensitive products.2. PCB Soldering Jigs and Fixtures
- Wave Soldering Fixtures: High-temperature resistant (up to 200°C short-term), long service life - PCB Test Fixture Insulation Blocks: Wear-resistant, precision machined - SMT Trays: Holds PCB semi-finished products with stable dimensions3. Display Equipment
- Advertising Display Boards: After surface treatment, can be silk-screen printed or spray painted, widely used in mall promotional displays - Showcase Decorative Shelves: High-density phenolic sheet polished to a smooth, high-quality surface finish - Signs and Nameplates: After engraving or electroplating, produces various identification markingsPhenolic Sheet vs. FR4: Which to Choose?
| Comparison | Phenolic Sheet | FR4 Fiberglass Board |
|---|---|---|
| Cost | ★★★☆☆ (Low) | ★★☆☆☆ (Medium-High) |
| Mechanical Strength | ★★☆☆☆ (Moderate) | ★★★★☆☆ (High) |
| Dielectric Performance | ★★★☆☆ (Good) | ★★★★☆☆ (Excellent) |
| Machinability | ★★★★★ (Excellent) | ★★★☆☆ (Good) |
| High-Temperature Resistance | ★★☆☆☆ (120°C) | ★★★★☆ (170°C+) |
| Recommended For | Low-cost fixtures, displays, transformer insulation | New energy, high-frequency, high-voltage insulation |
Conclusion: Choose phenolic sheet for budget-sensitive applications with operating temperatures ≤120°C; choose FR4 for high-voltage, high-frequency, and high-reliability scenarios.
Chaorong Electronics Phenolic Sheet Services
- Full Sheet Sales: 1220×2440mm standard large boards, cut to size as needed - Precision Machining: CNC cutting, drilling, routing, chamfering - Surface Treatment: Grinding and polishing, painting, silk-screen printing - Small-Batch Customization: Minimum order quantity of 1 piece, emergency orders responded within 24 hours
Contact Dongguan Chaorong Electronics Co., Ltd. (No. 2, Desheng West 1st Street, Gaobu Town, Dongguan, Guangdong) for the latest phenolic sheet quotes and machining solutions.