PA66 vs. PA6 Thermal Barrier Strips: A Professional Performance Comparison and Selection Guide

In the field of thermally insulated aluminum alloy doors and windows, glass-fiber reinforced polyamide thermal barrier strips are a core component. Among the available options, PA66 (Nylon 66) and PA6 (Nylon 6) are two common materials. However, PA66 significantly outperforms PA6 in overall properties, making it the more professional and reliable choice.

Core Difference: Molecular Structure and Thermal Stability

The most fundamental difference between PA66 and PA6 lies in the regularity of their molecular chains. This results in PA66 having higher crystallinity and stronger intermolecular forces, thereby granting it superior high-temperature resistance.

The notable advantages of PA66 thermal barrier strips are evident in the following three areas:

1. Higher Heat Resistance and Dimensional Stability

• The heat deflection temperature of PA66 GF25 can reach above 240°C, whereas PA6 is typically below 180°C.

• Under summer exposure or high-temperature conditions, PA66 strips effectively resist the significant stress caused by thermal expansion and contraction in the profiles, maintaining dimensional stability and preventing risks like loosening, deformation, or even glass breakage. PA6, conversely, carries the risk of softening and deforming at high temperatures.

2. Superior Mechanical Strength and Durability

• PA66 inherently possesses higher mechanical strength and rigidity. When reinforced with 25% glass fiber (GF25), its tensile strength, elastic modulus, and notched impact strength comprehensively surpass those of PA6 GF25.

• This enables PA66 strips to better withstand the weight of the window sash and long-term wind load pressures, ensuring the overall structural integrity and extended service life of the doors and windows.

3. Better Matched Coefficient of Linear Thermal Expansion

• The coefficient of linear thermal expansion of PA66 GF25 most closely matches that of aluminum alloy. When ambient temperature changes, the PA66 strip and aluminum profile expand and contract synchronously, working in perfect coordination. This significantly reduces internal stress caused by thermal expansion mismatch, fundamentally guaranteeing the long-term bond strength of the composite profiles.

While PA6 thermal barrier strips offer a slight cost advantage, their shortcomings in critical performance indicators—such as heat resistance, mechanical strength, and dimensional stability—pose risks to the long-term safety and functionality of doors and windows. In contrast, PA66 GF25 thermal barrier strips, with their superior overall performance, have become the inevitable standard for high-end energy-efficient doors and windows worldwide and the definitive choice for professional applications. To ensure optimal performance and durability, it is essential to explicitly specify PA66 GF25 material during selection.