Do you know what material the thermal break strips in your home's broken-bridge windows and doors are made of?
Release date:
2025-09-01
The function of the thermal break:
Simply put, thermal-break aluminum alloy is created by splitting the original solid aluminum profile into two separate pieces—then rejoining these two parts using mechanical composite techniques with two thermal break strips. The unique properties of these thermal break strips require them to simultaneously exhibit both exceptional strength and extremely low thermal conductivity. Otherwise, either significant quality risks could arise in thermal-aluminum doors, windows, or curtain walls (e.g., insufficient strength might cause the thermal aluminum profiles to fracture at the strip connections), or the insulation function would be compromised altogether (high thermal conductivity would undermine the material’s ability to effectively block heat transfer). That’s why the selection of materials for the thermal break strips and the precision of their manufacturing process are absolutely critical.
Types of thermal break strips:
Currently, there are two main types of thermal break strips used in aluminum doors and windows on the market: one is the PA66 thermal strip, and the other is made from PVC material.
1. PA66 Insulation Strip: PA66 is a series of modified engineering plastic alloys known for their high melting point, excellent heat resistance, and self-extinguishing properties. However, unmodified PA66 material doesn’t match aluminum alloy in terms of tensile strength and linear expansion coefficient. Through experimentation, adding 25% glass fiber to PA66 has proven to be the optimal solution, transforming it into an engineered plastic that serves as the ideal base material for insulation strips. Currently, no more rational or cost-effective new material for insulation strips has been discovered on the international market.
2. PVC Insulation Strip: The main raw material is PVC resin powder mixed with 25% calcium carbonate.
The difference between the two:
1: Tensile Strength
PA66 Insulation Strip > 126 N/mm
PVC insulating strip, approximately 70 N/mm
2: Heat Deflection Temperature:
PA66 Insulation Strip, 240°C
PVC Insulation Strip, 90 Degrees
3: Aging Resistance:
PA66 thermal break strips are durable and resistant to aging.
PVC insulating strips are prone to aging.
4: Coefficient of expansion:
PA66 thermal break strip has a coefficient of thermal expansion that matches aluminum alloy.
PVC insulating strips have a vastly different coefficient of thermal expansion compared to aluminum alloys.
How to identify:
1. To check for glossiness, note that the PA66 insulating strips used in broken-bridge aluminum windows have a matte, textured surface with a slightly darker hue; in contrast, the PVC insulating strips appear perfectly smooth and glossy, with a noticeably whiter color. A simple side-by-side comparison clearly highlights the difference between the two.
2. Another point to note is that the PA66 thermal break is non-combustible, whereas the PVC thermal break will catch fire after being lit for a short time, producing small flames—and you’ll even notice the typical smell of burning plastic.
3. The PA66 thermal break snaps after just one or two bends, whereas the PVC thermal break requires more than ten bends before it breaks.
4. When broken, the PA66 thermal break produces a crisp sound and leaves a clean, undistorted fracture surface that can be easily rejoined. In contrast, the PVC thermal break results in a white, deformed fracture when broken.
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Contact Information
Contact Address: No. 7, Industrial Avenue East, Songxia Industrial Park, Shishan Town, Nanhai District, Foshan City
Warren Doors and Windows, south of Fangshan Road and west of Dongtai Road, Dongcheng Subdistrict, Linqu County, Weifang City, Shandong Province
Become A Deaters :Info@wolunmc.com
National customer service hotline:+86 400-676-9888
WhatsApp:+86-18866798677
Beijing customer service phone number:+86 010-68319888
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