Introduction
Isola 185HR is a high-performance laminate and prepreg system designed for advanced multilayer printed circuit boards (PCBs) requiring maximum thermal stability, mechanical reliability, and electrical performance.
Built on Isola’s proprietary resin technology and reinforced with premium E-glass fabric, 185HR is ideal for high-speed digital, aerospace, defense, and industrial control applications where signal integrity and long-term reliability are essential.
Key Features
1. High Thermal Performance
-
Glass Transition Temperature (Tg): 180°C (DSC) / 185°C (DMA)
-
Decomposition Temperature (Td): 340°C @ 5% weight loss
-
Low Z-axis Expansion: Ensures excellent plated-through-hole (PTH) reliability
-
Lead-free Compatible and RoHS Compliant: Fully compatible with modern assembly processes
-
Thermal Stress Resistance: T260 = 60 mins, T288 > 15 mins
The high Tg and low CTE characteristics make 185HR ideal for designs exposed to multiple reflow cycles, thermal cycling, or harsh operating environments.
2. Superior Electrical Performance
-
Dielectric Constant (Dk): 4.0 @ 1 GHz
-
Dissipation Factor (Df): 0.020 @ 1 GHz
-
Stable Electrical Properties: Maintains consistency across frequency and temperature ranges
-
High Volume and Surface Resistivity: Ensures signal isolation and minimizes leakage currents
These properties make 185HR highly suitable for high-speed digital circuits, signal integrity-critical designs, and dense multilayer stackups.
3. Mechanical and Processing Advantages
-
Excellent Dimensional Stability: Minimizes warpage during lamination and drilling
-
Flexural Strength: 97,100 psi (lengthwise), 54,100 psi (crosswise)
-
Peel Strength: >1.06 N/mm after thermal stress
-
Closest to Conventional FR-4 Processing: Allows easy transition from standard FR-4 materials
-
AOI-Compatible: Laser fluorescing and UV blocking for high-speed automated inspection
Technical Specifications
| Property | Typical Value | Test Method / Notes |
|---|---|---|
| Tg (DSC) | 180°C | IPC-TM-650 2.4.25 |
| Td (5% wt loss) | 340°C | ASTM D3850 |
| CTE (Z-axis) | 40 ppm/°C pre-Tg, 220 ppm/°C post-Tg | IPC-TM-650 2.4.24 |
| Thermal Conductivity | 0.4 W/m·K | ASTM D5930 |
| Dk @ 1 GHz | 4.01 | HP4291A |
| Df @ 1 GHz | 0.020 | HP4291A |
| Peel Strength | >1.06 N/mm | IPC-TM-650 2.4.8 |
| Flammability | UL 94 V-0 | UL Certified |
| Moisture Absorption | 0.15% | IPC-TM-650 2.6.2.1 |
Applications
1. High-Speed Digital and Networking Equipment
185HR ensures signal integrity in servers, routers, and telecommunication base stations, where low loss and high thermal stability are critical.
2. Aerospace and Defense Electronics
Used in avionics, radar, and mission-critical control systems that require extreme reliability under wide temperature variations.
3. Multilayer PCB Designs
Optimized for high-layer-count PCBs and fine-line designs, ensuring robust interconnect reliability and minimal delamination risk.
4. Industrial and Automotive Electronics
Performs well in high-temperature, vibration-intensive, and power control environments, such as EV inverters or industrial automation.
Fabrication and Handling Guidelines
Storage and Handling
-
Store prepregs in cool, dry conditions to avoid moisture uptake.
-
Handle laminates with gloves to prevent contamination.
Drilling and Hole Preparation
-
Use new or resharpened drill bits to minimize resin smear.
-
Apply plasma desmear or permanganate process to ensure clean hole walls.
Lamination Process
-
Follow Isola’s recommended press cycle for consistent resin flow and bonding.
-
Compatible with vacuum lamination presses.
Assembly and Soldering
-
Designed for lead-free reflow processes up to 260°C.
-
Excellent through-hole reliability after multiple soldering cycles.
Advantages
| Benefit | Description |
|---|---|
| Thermal Reliability | High Tg and Td ensure stability under lead-free soldering. |
| Electrical Integrity | Low Df and stable Dk provide excellent signal performance. |
| Mechanical Strength | Resists delamination, bow, and twist during PCB fabrication. |
| Process Flexibility | Processes like FR-4 with no need for special handling. |
| AOI Compatibility | UV-blocking and fluorescing properties enhance inspection accuracy. |
Conclusion
Isola 185HR Laminate and Prepreg offer a balanced combination of thermal robustness, low dielectric loss, and mechanical durability, making it one of the most reliable materials for advanced multilayer PCB fabrication.
Whether used in high-speed computing, aerospace systems, or industrial control electronics, 185HR ensures consistent performance, high yield, and long-term reliability in demanding applications.
